1956 Journal of Applied Microscopy 



CLEANING AND PREPARATION OF SPECIMENS. 



The larger Helices should not be put into alcohol unless desired for ana- 

 tomical purposes, as it is almost impossible to remove the animal after it has 

 become hardened. They should be boiled as soon as possible. Dead snails 

 have a fragrance peculiar to themselves, and seldom make good specimens. The 

 water should be boiling, not simply hot. Species of about the same size should 

 be boiled together in order that the operation may be successful. A small wire 

 strainer with a long handle is very convenient for holding the snails while 

 boiling. If dropped directly into the water, there is apt to be trouble in fishing 

 them out and they are likely to be boiled too much. The time varies according 

 to the size and the species, some requiring more time than others. If not boiled 

 enough, the muscular attachment to the shell will not be loosened, and the 

 animal will not " pull " at all. If boiled too long, it is apt to break in two and 

 give a good deal of trouble before extraction. The time required varies from 

 ten seconds for a species of the size of Polygyra monodon to sixty seconds for 

 P. albolabris. It is well to experiment a little at first with a specimen or two of 

 each kind until the proper time is found. Only a few should be boiled at a 

 time, as they "pull " easier while warm. When boiled, the animal should be 

 slowly and carefully pulled out. Too much haste is apt to cause the animal to 

 break apart, leaving the apical whorls still in the shell. The curved points of 

 the collecting forceps are convenient for extracting the animals and hooks of 

 various sizes can be made from safety pins. By tying these on to small wooden 

 handles very effective instruments can be made. A small, fine-pointed dental 

 syringe is indispensable for this work. If the animal cannot be started with the 

 hook, or if it breaks in two, a jet of water from the syringe will usually solve the 

 difficulty. When the apical whorls are left in the shell, they can sometimes be 

 started by holding the shell carefully in hand so as not to crush it, and then 

 striking the fist sharply on the thigh of the operator. In case very desirable 

 specimens get into this predicament, putting them in alcohol for twenty-four 

 hours will contract the remnant of the animal sufficiently to enable the success- 

 ful use of the syringe. Many of the species have the aperture so obstructed 

 with teeth, that it is difficult to extract the animal with the hook. In such case a 

 vigorous use of the syringe will force enough of the body out of the shell to 

 enable the hook to be used. Frequently the whole animal can be forced from 

 the shell in this way, especially in the smaller forms. Patience and perseverance 

 will clean nearly every specimen. When the animal is completely extracted, 

 the interior should be thoroughly washed out with the syringe. A small piece 

 of sponge on the end of a fine copper wire, which can be bent in any direction, 

 is very useful for removing the mucous, which is apt to adhere to the interior of 

 the shell. This should always be carefully attended to, as it will greatly dis- 

 figure the specimen when dried. The exterior should then be thoroughly 

 scrubbed with a soft tooth or nail-brush. When perfectly clean, inside and out, 

 the water should be carefully emptied out and the shell put aside in the air, but 

 not in the sun, to dry. No oil or acid should be used on any of the land shells. 

 It is not desirable to attempt to clean the small species by removing the animals. 



