28 February 2009

The outstanding keyword for 28 February 2009

The list of keywords selected at a more or less random point during the day from the compilation for this blog at StatCounter:

28feb09Keywords

Today's outstanding search phrase is "jesus was an extraterrestrial". It links to this post.

We congratulate the anonymous searcher.

27 February 2009

Vultures disturbed

A couple of weeks ago while exploring the woods near my house, I interrupted the dinner of a group of vultures. It was unintentional; if I had known they were there before they knew I was there, I would have sneaked in to get some bloody good shots of them. Then again, I probably had no chance. My feeble human senses are no match for theirs.

When I first heard the peculiar sounds their wings make, I thought there was a squirrel on the tree I was examining for slugs (what else?). You can tell how clueless I was. Then I noticed some of them flying to the high branches of nearby trees.

vultures

I walked towards the spot where I thought the vultures had congregated to find out what they had been eating. Initially, I couldn't see anything unusual, but after my nose picked up an unpleasant scent, I looked around more carefully and spotted this recently died young deer.

deadeer

I hid behind a small tree not too far from the deer. I had the camera ready, hoping the the vultures would return to their feast, but they actually flew further away. They obviously knew all about the stupid human tricks I had up my sleeve.

26 February 2009

How to increase volume of a cylinder while keeping its surface area the same

Yesterday I noticed that someone searching the Web using the phrase “how do you make the volume of a cylinder greater without increasing the surface area” came to this blog. I didn’t check which specific post had gotten the hit, but it was probably this one. That post, however, didn’t answer the subject question. Then I got curious and decided to work out the answer.

Another way to state the question is can you increase volume of a cylinder while keeping its surface area the same? The answer is yes, one can increase the volume of a cylinder while keeping its surface area the same. One can do that only by increasing the cylinder's height (H) so that the volume (V) will increase, while at the same time, decreasing its radius (R) to keep the surface area (S) the same or by increasing R and decreasing H.

All we need are the following equations for V and S.

V=πR2H
S=2πRH + 2πR2

Let us look at the case when we increase H and decrease R. To get the new height (Hn) we multiply the old height (Ho) by a constant c>1 and to get the new radius (Rn) we multiply Ro by a constant k<1.

Hn = cHo
Rn = kRo

The new volume and the new surface area are

Vn = πRn2Hn = ckπRo2Ho
Sn=2πRnHn + 2πRn2 = ck2πRoHo + k22πRo2

The required condition Sn / So = 1 now becomes after proper substitutions:

Sn / So = [(ck)(2πRoHo) + k2(2πRo2)] / [(2πRoHo) + 2πRo2)] = 1

Let's simplify this by assuming that Ro = Ho = 1

Sn / So = (kc + k2) / 2 = 1

By rearranging, we get a relationship between c and k:

c = (2 - k2) / k

Remember that this is good only when Ro = Ho = 1.

Now let's try a numerical example. If we let c = 2, we get the following quadratic equation:

k2 + 2k - 2 = 0

The positive root is 0.732 (quadratic equation calculator). If we plug all the numbers in the appropriate equations and ignore the rounding off errors, we will get:

Vo = π
Vn = 1.464π

So = 4π
Sn = 4π

We have increased the volume while keeping the surface area the same.

Here is a new question: Is it possible to increase the volume of a cylinder while reducing its surface area?

25 February 2009

Definitely a crazy slug

CrazySlug

I photographed this Deroceras reticulatum last Friday night at 7:30 in my backyard under a rock. An hour and a half later, the slug was still there even though the temperature had gone down to -2.6 °C. How do they do it? I don't know. But they must be able to supercool their body fluids to avoid freezing.

The little yellow balls visible at the top are the slug eggs mentioned in this post (the millipede next to them was dead). Next weekend I may bring the eggs inside to see if the embryos have survived the sub-freezing temperatures we have had since I first saw them.

24 February 2009

How to take a slug's temperature and what you can learn from it


They don't put drawings like these into scientific papers anymore. Whenever I see such figures in old publications, I usually think of a "mad scientist" working in a cluttered basement lab late in the evening amid bottles of chemicals, glass vials, spark generators and a caged animal or two. Perhaps, one reason why editors now stay away from printing graphic descriptions of experimental setups is to prevent the association of such imaginary scenes with modern scientists.

This is Figure 1 from a paper by Hogben & Kirk (1944) with a bit of yellow color added by me to bring attention to their experimental subject, which happens to be a slug. But, no, they were not trying to reanimate a dead (or a half-dead) slug by infusing it with a secret elixir or passing thru it a high-voltage current derived from thunderstorm clouds. Their slug was alive, but had a thermocouple inserted into its foot (ouch!).

Hogben & Kirk were trying to demonstrate that the body temperatures of animals like slugs and earthworms whose external surfaces are always wet are not necessarily in equilibrium with the temperature of their surroundings, despite the fact that they are poikilothermic or cold-blooded. They did that by measuring the body temperatures of slugs and earthworms at different air temperatures and humidities.

In the experimental setup depicted in Figure 1, humidity was controlled by circulating the air above an appropriate solution of sulfuric acid in flask V thru chamber C where the slug was. The chamber and the flask appear to have been inside a constant temperature bath (B); the air temperature inside the chamber C was measured by a thermometer (D) and the humidity by a wet-bulb thermocouple (W).

I am summarizing their findings for the slug Arion ater in the graph below.

Hogben&KirkData
Data from Table 2 of Hogben & Kirk (1944). The green arrow is pointing at a barely visible point.

This is a "bubble plot": the areas of the circles ("bubbles") are proportional to the numerical value of the difference between the air temperatures and the body temperatures of slugs. There are 3 regions in the graph, which I marked with 3 different colors:

1. The orange circles show that when the humidity is low, there is a large difference (>10 °C) between the air temperature and the slug's body temperature more or less regardless of the air temperature. This difference arises from the cooling of the slug's body as its slime evaporates.
2. The yellow circles show that at moderate humidities, there is a moderate difference between the air temperature and the slug's body temperature.
3. The green circles show that when the humidity is high (>80%), there is a small, almost negligible, difference (<2 °C) between the air temperature and the slug's body temperature.

As Hogben & Kirk note, evaporative cooling of their bodies enables slugs to survive air temperatures that would otherwise kill them. They can keep their bodies cool as long as they have access to water to replenish what they lose thru evaporation. If they run out of water, however, they quickly succumb to heat and desiccation. That is exactly what happens when they get trapped on hot and dry sidewalks in the summer (example).


L. Hogben & R. L. Kirk. 1944. Studies on Temperature Regulation. I. The Pulmonata and Oligochaeta. Proceedings of the Royal Society of London. Series B, Biological Sciences, 132:239–252. Download a free copy before the end of March.

23 February 2009

22 February 2009

How a slug breathes—Part 2

Here is another movie I just made by taking sets of sequential pictures and then combining them in Windows Movie Maker. This one shows the eastern U.S. native slug Megapallifera mutabilis.

video

Note the slug's pneumostome (the breathing hole) towards the back of its head. In the beginning of both sequences, the pneumostome was open and then it closed.

The slug didn't like the bright lights I had shining on it and so it kept turning away from the camera. Hand-holding the camera at high magnifications invariably introduces instability. I may have to get a table top tripod.

My 1st gastropod movie was here. Part 1 of this series was this post from April 2006.

20 February 2009

Reproduction of Rumina saharica

Rumina saharica is one of the land snail species with decollated shells originating from the Mediterranean area. They have been introduced to many parts of the world far away from their homelands.

A short paper of mine on the mating as well as selfing (reproduction without mating) of Rumina saharica was published in the Zoology in the Middle East near the end of last year. I just uploaded a pdf copy of the paper here.

A brief description of the mating of Rumina saharica and a color picture of mating snails are in this post.

19 February 2009

Kahuli or the singing snails of Hawaii

When up the mountains of Oahu I heard the grandest but wildest music, as if from hundreds of Aeolian harps, wafted to me on the breezes, and my companion (a native) told me it came from, as he called them, the singing shells. It was sublime. I could not believe it, but a tree close at hand proved it. On it were many of the shells, the animals drawing after them their shells which grafted against the wood and so caused a sound; the multitude of sounds produced the fanciful music.
Rev. H. Glanville Barnacle, 1883. Musical sounds caused by Achatinellae. Journal of Conchology 4:118.
In his 1909 book Unwritten Literature of Hawaii: The Sacred Songs of the Hula, Nathaniel B. Emerson offered a more plausible explanation for the source of the music Barnacle had heard (p. 121):
The natives are persuaded that these shells have the power of chirping a song of their own, and the writer has often heard the note which they ascribe to them; but to his ear it was indistinguishable from the piping of the cricket.
Achatinella
From N.B. Emerson, Unwritten Literature of Hawaii: The Sacred Songs of the Hula, 1909.

Henry Pilsbry, although he himself probably didn’t think snails could produce music, considered this a significant enough piece of information to be included in the Manual of Conchology (vol. 22, p. xxxvi, 1912-1914):
The native Hawaiians claim that the tree shells have a song, which they have fancifully supplied with words. Dr. Newcomb (P. Z. S. 1853, p. 129) and Dr. N. B. Emerson (Sacred Songs of the Hula, p. 121), and others have given versions of this song. Mr Perkins believes it to be the chirping of crickets.
Writing about the crickets in Natural History of Hawaii a few years later, William A. Bryan also sided with the arthropods (p. 430):
Their chirp can usually be heard a long way, and as they occur in localities frequented by tree snails, their song is often spoken of by the layman as the chirp of these tree-dwelling animals.
Yesterday I asked about this to the malacologist Carl Christensen of Hawaii. His response reiterated the cricket theory:
Pilsbry (and all other modern malacologists) regarded this as a pleasant bit of mythology. It's the crickets. There was a real basis for the association, though--the snails and crickets have similar requirements with regard to moisture. When I was first introduced to Achatinella in the 1960s by Yoshio Kondo, he taught us to listen for the crickets when we went up into the mountains, because once we started hearing crickets we should start looking seriously for Achatinella. It worked particularly well in the trails in the Tantalus area, on the ridge between Manoa and Nuuanu Valleys behind Honolulu. Of course, the snails are gone from there now (though I think the crickets survive).
I hope the crickets are still singing in memory of their once abundant habitat-mates.

18 February 2009

Stuck between Arthurine and Bauer

Here is a rather useless piece of information: according to whitepages.com my name, Aydin*, is the #18,217 ranked 1st name in the U.S.

18217

But I am the one and only "Aydin Orstan" in the U.S. and probably also in the entire world.

The same source also informs us that according to their records, in the U.S. there are only 30 people named Eckel (I once met one of them), 104 people named Jebediah, 247 people named Aydin, 478 people named Remus and 880 people named Jethro (remember Jethro Tull?).


*The correct Turkish spelling is with an undotted "i", or Aydın.

17 February 2009

Republish or reperish

Artists, especially painters and composers, often revise their own public creations. Beethoven, for example, is known to have revised many of his compositions over and over again.

Sometimes I wish scientists had developed a tradition of republishing revised versions of their papers. Certainly, such a tradition exists for books, especially for textbooks in which case it is done mostly for commercial reasons. But the practice is definitely not limited to textbooks. For example, there were several revised editions of Charles Darwin’s On the Origin of Species.

If it were acceptable to publish new, improved version of old papers, one could correct any mistakes in the original, add new data, modify the interpretations. A revised republication would be quite useful in those cases when an author had collected a small amount of new data in a research project that he/she had already written about and if the quantity of the data wouldn’t otherwise justify the writing of an entirely new paper. A revision would also be warranted when the authors’ interpretations of their data had changed significantly since the original publication. Republished manuscripts would retain the original title but would be marked clearly to indicate that they were revised versions of previously published papers. That way tenure-seekers wouldn't be able to inflate their resumes by repeatedly republishing the same old stuff with only minor changes.

Perhaps with the further development and acceptance of on-line publishing, the practice of republishing revised papers will gradually arise.

16 February 2009

Down among the spices of the Spice Bazaar

One of the 2 most famous covered bazaars in Istanbul is the Spice Bazaar or Mısır Çarşısı (Egyptian Bazaar) as it is know in Turkish*. Last October we spent some time there sampling the goodies and buying a few small bags of spices.

SpiceBazaar1

As its name implies, the place specializes in spices, but other related foods as well as the usual touristy junk are readily available. Here is a cute shopkeeper presenting her wares.

SpiceBazaar2

There were all sorts of teas. Here we have from left to right, orange tea, apple tea, kiwi tea, lemon tea and cherry tea. The brightness and the hues of the colors suggest they were all artificial.

SpiceBazaar4

They seemed to specialize in gelatinous sweetmeats with lots of nuts in them.

SpiceBazaar3

And, of course, there was something to cure almost every ailment or to improve one's performance in any imaginable activity. Who needs Viagra when there is Turkish Viagra?

SpiceBazaar5

No, I didn't need to buy any of that. I am talking about 6 times in the night without any enhancers.


*The other one is Kapalı Çarşı, the Covered Bazaar.

15 February 2009

I do have an axe

ax

Certain anonymous comments* posted by one or more readers after this recent post has prompted me to list these reminders to my dear readers.

1. Despite the Santayana quote in the sidebar, yes, I have an axe that gets dull occasionally and needs grinding. This is not your run-of-the-mill newspaper or magazine where the editors do their best not to offend their readers' cherished beliefs and even bend over backwards to reinforce them. That's because they are afraid of losing their sources of income. Here is a piece of news for you, in case you haven't noticed: newspapers don't exist to bring you the news; they exist to bring you the advertisements.

But I don't have such concerns. As already stated in this post, one purpose of this blog is to inject my opinions into your minds. If you don't like a particular post, ignore it or leave a proper comment. If you don't like this blog, don't read it.

2. This is my blog. That means I can insult you, but you can't insult me. All insulting comments have been and will be deleted (that's when the ax comes in handy). If you want to insult me, do it on your blog. I wouldn't read it and I couldn't care less.

3. If you have something important to say in your comment, put your name under it. What are you afraid of?

4. Make sure your comments are relevant to the original context of the post you are commenting on. Totally irrelevant and nonsensical comments with links to commercial sites are also deleted as well as the comments with links to creationist (=intelligent design) sites.

5. If you get insulted whenever I or someone else criticizes or ridicules your cherished beliefs, I seriously think you have insecurities and uncertainties about what you believe is true. Maybe it's time you considered switching over to our side. Let's remember what John Lennon said: You may say that I'm a dreamer. But I'm not the only one. I hope someday you'll join us.

Thank you for reading this blog.


*Including one comment I had to delete.

14 February 2009

An almost perfect Valentine’s Day card for a malacologist

SnailCard

A Valentine’s Day card from a long-time admirer of yours truly displays on it, quite fittingly, a snail. Though the snail may appear to be as happy as a snail can be—provided that they have such feelings—a close inspection reveals that it has a backward shell. The opening of it is supposed to be above the snail's head.

But it’s the thought that counts.

I wish everyone a slimy Valentine’s Day!

13 February 2009

February tick

FebruaryTick

Obviously slugs were not the only critters that were woken up from their winter slumber by the unusually warm weather during the first half of this week. I found this deer tick (Ixodes scapularis) crawling up my pants' leg late Wednesday afternoon in the woods. It was moving up my leg surprisingly fast for a tick. Perhaps it had a way of sensing that to get a head start in the game of reproduction it needed to latch on to a warm mammal quickly before the freezing temperatures returned.

Luckily I saw it before it could locate a passageway thru my pants to my tender skin. I left it on a nearby log. Maybe a deer passed by that spot during the night.

No miracles this time

God was looking the other way when a Continental Connection airplane crashed last night near Buffalo killing 49 people with no survivors.

12 February 2009

Snails and deer poop

Parelaphostrongylus tenuis (brainworm) is a nematode that infects the brain of the white-tailed deer (Odocoileus virginianus). Although the nematode doesn’t usually cause any apparent illness in deer, there is quite a bit of interest in its life history and transmission, because it can also infect caribou, reindeer, sheep, goats, etc., often leading to the death of those animals.

I have some interest in P. tenuis because terrestrial gastropods are the intermediate hosts of the nematode’s larvae. The nematode larvae are found in deer feces and the snails are believed to get infected with the larvae when they crawl over the feces. Presumably, the nematodes pass on to the deer or the other animals when they ingest infected snails accidentally during browsing (I don’t think the deer or the other susceptible animals eat snails intentionally).

Terrestrial gastropods don’t seem to mind to supplement their diets with feces whenever the opportunity arises (for example, read this post and also this one). So, expectedly, several studies have examined the consumption of deer feces by snails. The most recent study that I am aware of is by Garvon & Bird, published in 2005. (Again, I haven’t been that interested in this subject to have spent time searching for more recent papers.)

Garvon & Bird provide a brief review of the previous reports in the literature: one study claimed that the snails were repelled by fresh deer feces, but not weathered ones, while another study claimed that snails were repelled by deer feces containing P. tenuis larvae. The results of Garvon & Bird introduce further confusion. They found that the snail Anguispira alternata was attracted to fresh deer feces whether or not they contained P. tenuis larvae, although the snails seemed to prefer larvae-free feces to those containing larvae.

All of this popped in my mind late yesterday afternoon when I was passing by some deer poop in the woods. So I stopped to investigate.

DeerPoop2

But my poking around with a stick produced no snails. Perhaps I will have better luck in the spring and the summer.


Garvon, J.M. & Bird, J. 2005. Attraction of the land snail Anguispira alternata to fresh faeces of white-tailed deer: implications in the transmission of Parelaphostrongylus tenuis. Canadian Journal of Zoology 83:358–362.

11 February 2009

Marissa and her shadow in the afternoon sun

Marissa&Shadow

The spring-like weather is continuing. According to the National Weather Service, the afternoon temperature went up to 21 °C (70 °F). But they are also predicting that the winter will return towards the end of the week.

Snail's Tales in BBC Knowledge

The BBC Knowledge magazine has a link to your favorite blog about gastropods (and everything else) in their December 2008 issue. It's on the bottom left-hand corner of p. 94. If you click on the link you will...well, return to this blog. Yay!

10 February 2009

Return of the slugs

The unseasonably warm weather we’ve been having since last Saturday has thawed the soil that was frozen last Friday. I am amazed how quickly life returned to the undersides of the rocks. Already on Sunday afternoon there were slugs, isopods and other arthropods in places that had been barren 2 days earlier. I looked under 6 rocks and saw 3 live slugs. This Deroceras reticulatum was one of them.

FebruaryDeroceras

When I was looking at this picture on my computer I saw those yellowish little balls in the mud below the slug. They looked like slug eggs, but I hadn’t noticed them while taking pictures. I went back out and looked under the same rock. Sure enough, they were there and they were indeed slug eggs. I don’t know if the slug in the picture had laid them and if they will survive when the soil freezes again.

This observation demonstrates that what appear to be adults of at least some slug species survive the sub-freezing temperatures of the winter. Now I need to figure out where they hide when the ground is frozen. The National Weather Service is predicting that the next Friday night the temperature will dip below freezing again. I will be monitoring the slugs and those eggs.

09 February 2009

Acceptable after revisions

A few hours ago I received an e-mail from the editor of the American Malacological Bulletin about my manuscript on Oxyloma retusa, which I had submitted back in October of last year.

Both reviewers recommended that the manuscript be accepted after some revisions. The suggested revisions are mostly minor, but there are quite a number of them. So it's going to take a while to revise the manuscript before I can send it back to the editor. But, hey, it's all part of the game and the end is near.

How to create a perfect predator

For starters, you can take an already good predator, for example, a cat, and make it invisible. In H. G. Wells' The Invisible Man, Griffin, tells Kemp, his momentary confident, the story of how he experimented on a cat before turning his invisibility machine on himself.

The bones and sinews and the fat were the last to go, and the tips of the coloured hairs. And, as I say, the back part of the eye, tough iridescent stuff it is, wouldn’t go at all...About two, the cat began miaowing about the room. I tried to hush it by talking to it, and then I decided to turn it out. I remember the shock I had when striking a light—there were just the round eyes shining green—and nothing round them. I would have given it milk, but I hadn’t any. It wouldn’t be quiet, it just sat down and miaowed at the door. I tried to catch it, with an idea of putting it out of the window, but it wouldn’t be caught, it vanished. Then it began miaowing in different parts of the room. At last I opened the window and made a bustle. I suppose it went out at last. I never saw any more of it.
An almost invisible cat at large! Watch out rats, mice and the pigeons!

NotYetInvisibleCat
Not yet fully invisible. I need to make some fine tuning.

Griffin didn't mention if the things he made invisible retained their odors. If they did, an invisible cat's potential prey could still detect its presence by its odor.

Later in the story, when the violence-prone invisible man is on the run, Kemp reveals one of Griffin's secrets to the posse after him:
“Bear in mind,” said Kemp, “his food shows. After eating, his food shows until it is assimilated. So that he has to hide after eating.
What about the feces? That is never explained in the book either.

08 February 2009

Lights, camera, slooow action!

Here is my 1st attempt at creating a movie by taking sets of sequential pictures and then combining them in Windows Movie Maker. It shows a Tridopsis coming out of its shell. It is one of those species that has been on this blog before several times (for example, here and here) and still not been identified.

video

Now allow me to be my own critic. The 2 main problems were: (1) the lights were not bright enough; (2) I didn't get close enough to the snail. Afterwards in Photoshop, I had to increase the brightness of all the shots and also crop them, which ended up taking quite a bit of time. The other problem is that because the camera was hand-held and because I was changing its position with respect to the snail between sets of sequential shots, the resulting film is choppy. I think cropping also contributed to choppiness. Nevertheless considering that I wasn't using a video camera, it's not too bad, is it? The best part I like is where the snail flips its shell over at the end.

All the pictures were taken with an Olympus E-500 in the sequential mode with the picture quality set at SQ to decrease the size of the individual pictures. The total number of pictures combined was 109.

The next one will be better.

06 February 2009

Where do the soil animals go in the winter when the soil is frozen?

From early spring thru late fall, there will be some slugs and isopods underneath almost every large enough rock in my backyard (for example, see this post). But one day last January when the air temperature was -13 °C, I looked under several rocks and could not see any animals, active or frozen. Of course, that wasn't too surprising, for the soil underneath the rocks was frozen solid and the undersides of the rocks were covered with ice crystals. In fact, I had to use a small shovel to pry the rocks off the ground to which they were glued by ice.

I am pretty sure I will find the slugs and the isopods again in the spring. So then, where are they now? If they all died during the first frost, where will the new ones come from in the spring? If some are surviving, where are they hiding now?

One likely answer is that the slugs and the isopods migrate deep into the soil thru the cracks and the holes (earthworm burrows?) and wait out the winter in a semi-dormant state; hibernation may be a suitable description of their state.

Soil has 2 characteristics that could definitely contribute to the winter survival of soil-dwelling animals: 1. the diurnal temperature fluctuations that take place on the surface dampen with depth; 2. temperature rises with increasing depth. The following figure shows the variation of average temperature with depth and time under bare soil in St. Paul, Minnesota in January (the number above each curve is the depth).


Figure 2.2 from Microclimate: The Biological Environment by Norman J. Rosenberg, Blaine L. Blad, Shashi B. Verma, 2nd ed., Wiley-Interscience, 1983. (Google Books)

The lowest temperature (-10 °C) and the widest fluctuations were at the surface, while the highest temperature (about -2.5 °C) was at a depth of 80 cm and stayed more or less constant during the day.

I wanted to determine if something similar was taking place in my backyard. So this morning I took some soil temperature measurements. The procedure was simple: Using a long screw driver and a hammer I drilled a vertical hole in the ground under a rock, stuck a long, glass thermometer in the hole, waited for about 10 minutes, recorded the temperature and the depth. And then repeated this for different depths in soil under 2 rocks. Here are the results.

SoilT

Between 10 and 11 in the morning, air temperature about 1 cm above the soil was -2 °C. The soil under the rocks was frozen and, as before, there were no animals under the rocks. However, at a depth of 23 cm below the 1st rock, the temperature was 1 °C. Interestingly, at comparable depths the soil under the 2nd rock was slightly colder than that under the 1st one.

Although these data do not demonstrate that the missing animals are hiding deep in the soil, it does indicate that if they could migrate to depths more than about 20 cm, they would avoid freezing temperatures. Both the thermometer and the screw driver were coming back up with mud on them, which showed that at those depths the soil was not dry and therefore, there would be no danger of dehydration for the animals.

05 February 2009

The shell of Limax maximus

As promised in this post, here is a picture of the vestigial shell of the slug Limax maximus.

LimaxMaximusShell

I cut along the back border of the mantle and then folded it over. The head of the slug is to the right. The shell sits under the mantle in a chamber called the shell sac. Immediately under the shell is the lung. I believe the spongy tissue under the shell and opposite to the lung in the picture is the kidney. The scale is in millimeters.

04 February 2009

An afternoon in an old Jewish cemetery in Istanbul

One sunny and pleasant afternoon last October my friend Nemo Ramjet (not his real name) took me to the Nakkaştepe Jewish Cemetery in the Kuzguncuk district of Istanbul. We wanted to photograph the tombstones and, of course, collect snails. To enter the cemetery we climbed over a high metal fence like a couple of school boys sneaking into a forbidden garden. Only much later, at the end of our expedition did we realize that there was a regular entrance for the use of perhaps slightly more normal people.

The cemetery consisted of an old section on a gentle slope overlooking residential districts and a presently used smaller section on a facing hillside. We concentrated our efforts in the old section where many marble tombstones were scattered, some haphazardly, over the hillside.

KuzguncukCemetery1

Several of the tombstones had rather pleasant and artful engravings on them.

KuzguncukCemetery4

And the late-blooming wildflowers were dissipating the gloominess of the surroundings and turning our work into a more pleasant endeavor.

KuzguncukCemetery5

Most of the old gravestones had been inscribed in Hebrew, which neither of us could read, but a few were in European languages. This partially broken bilingual one belonged to a Wolf Goldenberg who died in 1882.

KuzguncukCemetery3

The oldest grave whose inscriptions we could read was from 1869. The name on it appears to be Doctor Marco Dalmedi[co]*.

KuzguncukCemetery2

Subsequent research revealed that the Nakkaştepe Jewish Cemetery was much older than the oldest tombstone we found. Brewer (1830) mentioned a visit in 1827 to a "Jewish burying-place near Coos-Conjux on the Asiatic side [of Istanbul]" that was undoubtedly the same cemetery in Kuzguncuk, while according to Rozen (2002), the oldest Jewish tombstone in Kuzguncuk is from the 16th century.

A manuscript about the snail shells we collected is in press and will be the subject of a future post.


*Another tombstone belonged to a Raphael Dalmedico.

Brewer, J. 1830. A Residence at Constantinople, in the Year 1827. Durrie & Peck, New Haven. (Google Books)
Rozen, M. 2002. A history of the Jewish Community in Istanbul: The Formative Years, 1453-1566. Brill, Leiden. (Google Books)

03 February 2009

How to perform CPR on a slug

A reader who had recently lost a "beloved" pet slug e-mailed this inquiry: Can slugs have heart attacks?

Interesting question. But first, what do we mean when we say a human has had a heart attack? MedicineNet describes a heart attack as follows:

The death of heart muscle due to the loss of blood supply. The loss of blood supply is usually caused by a complete blockage of a coronary artery, one of the arteries that supplies blood to the heart muscle. Death of the heart muscle, in turn, causes chest pain and electrical instability of the heart muscle tissue.
If this leads to irregular heart beats or to the complete stopping of the heart, then the blood flow, and consequently the oxygen supply to the brain will stop. If the heart beat is not restored within about 5 minutes permanent brain damage or death will follow.

The circulatory anatomy of gastropods (slugs and snails) is rather different than that of humans. The best description of the gastropod vascular system has been given by Fretter and Graham1 for the semi-terrestrial snail Littorina littorea.
Arteries distribute the blood to the main parts of the body, branching over and over again until they are minute and end by pouring their contents into a series of blood spaces around the main organs and in between the muscles and connective tissue layers of the body. From this series of spaces other vessels take the blood to the excretory and respiratory organs, whence it is returned to the heart. The vascular system of [Littorina littorea] differs from the more familiar vertebrate pattern in a number of important respects: the heart receives primarily oxygenated blood to circulate to the body...; there is no capillary system between the arteries and veins but a series of indefinite haemal spaces, though these are not necessarily of dimensions very different from capillaries. All the organs are directly bathed in blood, and the circulation must be slower than in the vertebrate and less definite in its course.
Gastropods don't have coronary arteries either. But I suppose a blockage could develop in one of the main blood vessels. Such a blockage would certainly interfere with the functioning of a slug's heart and the circulation of blood throughout its body. But I suspect that if a slug's (or a snail's) heart stopped beating for whatever reason, the slug wouldn't just drop to the ground and pass out—it's already flat on the ground, to begin with—but would continue to carry on its sluggish activities until the oxygen concentration of the blood in the blood spaces became about equal to that of the tissues. At that point the diffusion of oxygen from the blood to the organs would stop and the slug would probably become quiescent for a while, lowering its metabolic rate and thus reducing its oxygen requirement. But, if its blood circulation didn't recover, it would sooner or later die.

In humans, the word "attack" in the phrase "heart attack" implies a quickly worsening condition with a sudden onset and a potentially detrimental outcome. If my reasoning is correct, in slugs and snails, on the other hand, even if the onset of a pathological condition in the heart were sudden, its effects on the overall well-being of the animal would be gradual. Therefore, there would be no "attack", so to speak. Forget the CPR, then.

limax2
A slug in intensive care. It didn't recover and may have died of stress-induced multiple organ failure.

If you think your slug has eaten too much and is suffering from heartburn instead, give it one tablet of Hajmola and e-mail me in the morning.

Finally, I send my deepest condolences to my reader. I hope you didn't forget to pickle your loved one in alcohol. Send it over and I'll perform an autopsy. That may help us determine what killed it. May your next slug live longer.


1. Fretter & Graham. 1994. British Prosobranch Molluscs.

02 February 2009

Where old tires go to become sailors

Boat&Tires

This picture shows the tires of all kinds lining up the sides of passenger ferries and docks in Istanbul, Turkey. There must be a vast empire of collectors, buyers, suppliers, distributors, traders and sellers of used tires. This is, of course, a good way to recycle a commodity that would otherwise end up in a garbage dump

Boat&Tires2

The utility of old tires from trucks and tractors as bumpers to protect boats and piers must have been discovered independently in many harbors of the world during the last century. But how did they come up with the idea in the very beginning? First, there was probably a rapidly growing accumulation of used tires that people didn't know what to do with. At the same time, being the frugal people they are, they didn't want to just throw the tires away in garbage dumps; very few potentially usable things were ever thrown away by those surviving in perennially weak economies. And then someone who was aware of those surplus old tires must have been on a boat one day when he had a sudden enlightment, a spark in is mind: Hey, we can tie old tires around this boat to dampen its collision with the dock!

But what were they using before then? Old pictures of the Istanbul harbor may answer that question and also establish the approximate date of the beginning of the practice of using tires.