132 ELEVENTH REPORT. 



PRESERVATION OF CAT8 FOR DISSECTION. 

 Jesse J. Myers. 



In 1904 it became necessary for us to ]:)rovicle some method whereby we 

 might preserve cats for a number of weeks, while they were being dissected. 

 After five years of experiments, many of which were unsatisfactory, Ave 

 have arrived at certain methods and conckisions which may be of interest 

 to those who may care to preserve mammals for future dissection. 



The method we use at present is as follows: The animal is killed with 

 chloroform. It is then placed on a dissecting board, and a small incision 

 is made through the skin on the inner side of the I'ight thigh, exposing the 

 femoral vein. A small glass canula is inserted in the vein, with its point 

 directed toward the heart. The vein is then ligated below the canula to 

 prevent a flow through its other opening, and the canula is now connected to 

 a siphon that leads from a reservoir about five feet above the level of the 

 cat. In this reservoir has been placed about thirteen hundred c. c. of the 

 following embalming fluid: 



Carbolic acid crystals, 8 grams. 



Glycerine, 82 grams. 



Sodium arsenate, 137 grams. 



Formalin 4 per cent, 1000 cc. 



The animal is left in this position from two to three hours, or at least 

 until it ceases to receive more of the embalming fluid. A cat of average 

 size will take about one thousand c. c. of the fluid. The ])ressure has been 

 sufficient to rupture some of the smallest l)lood vessels of the abdomen and 

 so the abdominal cavity will l)e enormously distended with the embalming 

 fluid. To insure perfect injection of the head, neck and extremities, it may 

 be well to occasionally give these a slight massage. This we scarcely ever 

 do, however. If there has ]:)een sufficient injection of the head and neck 

 region it is usually indicated by a seepage from the nostrils, caused by the 

 rupture of small blood vessels. 



The animal should now be laid away for a few daj's before dissecting in 

 order to permit the fluid to penetrate. When the abdominal cavity is opened 

 the embalming fluid can he removed with a sponge, ami in a very short time 

 the tissues will lose their excessive moisture. At this point in the dissection 

 we are accustomed to inject the arterial system, lioth backward and forward 

 through the abdominal aorta at a point a little anterior to the renal arteries. 

 Plaster of Paris, mixed with water and a coloring agent, makes a very good 

 injection mass for all ordinary dissection work, and seems to. be more con- 

 venient than the starch injection mass most commonly used. 



With the exception of possil)le attacks of moulds the animal may now be 

 kept for weeks. At the close of each laboratory jjeriod we spray the interior 

 and uncovered parts of the cat with a weak solution of carbolic acid, using 

 for this purpose an injection syringe having a fine nozzle. The student is 

 then requested to wipe the cat as dry as possible, using a s])onge. The more 

 thoroughly this is done the better will be the later contlition of the animal. 

 The cat is then thoroughly wrapped with its own skin, Avhich has l)een only 

 partially removed, and thus laid away until when next needed. 



