358 Transactions of the Society. 



wliile glass, wood, &c., are too fragile for use. We have tliem made 

 of all diameters, but the most useful size for ordinary glass slides is 

 seven-eighths of an inch in diameter. 



When, therefore, we wish to examine the serous membranes, the 

 animal must be killed gently by chloroform ; indeed, as soon as it 

 is insensible it ought to be even drenched with the anaesthetic, which 

 seems, when thus given in excess, to anaesthetize the individual cells 

 as well as the animal. No time should be lost by injecting the 

 animal, as by doing so at first we missed some most valuable indica- 

 tions ; but immediately after death the abdomen should be opened 

 up to the fullest extent, a portion of the uterus or intestine seized 

 with the forceps, and gently lifted up, so as to stretch the membrane 

 which attaches it to the back of the abdominal wall. Upon one sur- 

 face of this membrane the smaller ring of the pair is applied, and upon 

 the opposite surface the larger ring is adapted, and pressed gently 

 with a slight circular motion upon the smaller ring, so as not to 

 ruptm-e the delicate membrane, until it jams itself upon that smaller 

 ring, with the membrane lying between them. It may now be 

 snipped off with fine scissors external to the rings, thus separating 

 it from the rest of the body of the animal ; and we have then a 

 miniature tambourine formed, in which condition the membrane 

 remains until finally disposed of. 



Our next step is to apply to either or both surfaces, with the 

 greatest care and without any preliminary washing, a half per cent, 

 solution of nitrate of silver in distilled water, and after a few 

 instants' exposure to its influence, the preparation is carefully 

 washed with distilled water, and exposed for a short time to a dull 

 northern light, until the desired action of the silver has been obtained, 

 as shown under the Microscope. We may now expect that not only 

 have the various cells forming the membrane been fixed in the con- 

 dition or shape they possessed during life, but that the shoals of 

 wandering cells, which are continually groping over the free surfaces 

 of the abdominal organs, will, as far as they existed upon the free 

 surface of our piece of membrane, be firmly fixed in situ, and the 

 whole may now be subjected to various staining processes. 



Of these, by far the most suitable and generally used by us for 

 such tissues is the process invented by one of us, and described three 

 years ago in the Journal of the Quekett Club. 



The tambourine membrane is first soaked for a few minutes 

 in spirit, to deprive it of water, and a 2 per cent, solution of 

 perchloride of iron in spirit is filtered upon it. After the lapse 

 of a few minutes a few drops of a 2 per cent, solution of pyro- 

 gallic acid in spirit is likewise filtered upon it, and in a few 

 minutes more, according to the depth of tint required, the whole 

 may be wjished in ordinary household water ; a few drops of glyce- 

 rine placed upon the membrane render it transparent, and it is 



