43 2 APPENDIX. 



water 95 parts). Into an adult cat 300 to 400 cubic centimeters of 

 the five per cent, formalin should be injected. 



The cat may now be preserved in a one per cent, solution of 

 formalin. Before immersing it in the formalin it is well to remove 

 the hair in some way, otherwise this will hold much water and be 

 very inconvenient in dissection. The neatest method is to cut off 

 the hair with scissors; this takes some time, however. If the skin- 

 muscles (p. 93) are not to be dissected, the skin may be removed. 

 It is well in this case to leave the skin on the sides of the head and 

 on the feet. 



It is not necessary to open the abdominal cavity, after injecting 

 with the five per cent, formalin. If there is at any time reason to 

 suspect that the viscera are not keeping well, the abdominal and 

 thoracic cavities should be filled with five per cent, formalin by 

 making a small hole through the body wall into the cavity, introduc- 

 ing a canula, and injecting till the cavity is full. 



The specimen should be kept in a jar or other vessel and should 

 be completely immersed beneath the one per cent, formalin. Any 

 parts projecting above the fluid maybe attacked by mould. If a 

 part is found to be moulded, it should be submerged, when the 

 mould will be killed. The mould injures the specimen if allowed 

 to grow for a long time, but if discovered soon, no very serious harm 

 results. 



During dissection, exposed parts of the body should be kept 

 from drying by covering with a damp cloth. Specimens preserved 

 in formalin dry out much less quickly than those preserved in 

 alcohol. 



2. For some purposes it is much more convenient to preserve 

 the material without immersing it in a vessel of formalin. Specimens 

 injected with five per cent, formalin, as above directed, would usually 

 keep perfectly without further treatment, but for two difficulties: 

 (i) the specimen may dry; (2) it may be attacked by mould. 



The drying may be prevented as follows : Use for injecting a 

 mixture of the five per cent, formalin with one-sixth its volume of 

 glycerine. This will dry only very slowly, and if pains are taken to 

 keep exposed parts covered with cloths dampened with the mixture 

 of formalin and glycerine, there will be no trouble from this source. 

 The skin should not be removed from such specimens except as 

 necessary in the course of dissection. The hair will give little 

 trouble, because dry. 



The specimens should be kept in a tight box, that the fluid may 

 not evaporate rapidly from the cloths' used for wrapping. 



The attacks of the mould present a difficulty not so easily over- 

 come. As long as the specimens are in daily use for dissection, and 

 exposed parts kept covered with cloths saturated with the glycerine 

 and formalin mixture, little or no trouble is to be anticipated. But 

 if the specimens are left untouched for some days, and particularly if 

 exposed surfaces are not kept covered in the manner above recom- 



