392 Pierre A. Fish 



The brain " fixed " in fluid No. i did not sink to the bottom 

 of the vessel until after six days. Within ten days it had lost 

 36 grams in weight, and 1.9 centimeters in girth, and had be- 

 come slightly distorted. The specimen in fluid No. 2 floated 

 for more than a week ; it also became somewhat distorted. 

 The loss of weight was 45 grams, of girth 2.3 centimeters, 

 being greater than in any of the others. Fluid No. 3 was 

 very rapid in its action and produced a very firm preparation. 

 The color was considerably lighter than in the ordinary bi- 

 chromate specimens. The loss of weight was 39 grams, of 

 of girth 1.3 centimeters. It should be noted with regard to 

 fluid No. 4, that the weight increa.sed 6 grams at the interme- 

 diate stage and that the girth was exactly the same as when 

 fresh. At the third stage, however, there was a loss of 36 

 grams in weight, and of 2 centimeters in girth, due without 

 doubt to the re-dissolving of the sublimate in the alcohol. 

 Fluid No. 5 gave a better final test than did an}' of the pre- 

 ceding. There was an increase of 8 grams in weight and of 

 0.6 centimeter in girth at the intermediate stage. The loss 

 of weight was 25 grams and of girth 0.6 centimeter. Treat- 

 ment with fluid No. 6 left the brain nearest to its original 

 weight and girth. There was a gain of 14 grams in weight 

 and of 0.7 centimeter in girth at the intermediate stage. Af- 

 ter more than four months from the date of its first treatment 

 it had lost only 7 grams in weight and \i'a.A.gainedo. i centimeter 

 in girth. The bichromate is nearly insoluble in alcohol, and 

 once having penetrated the tissue thoroughly, it remains ; the 

 replacement of the natural water of the tissues is so gradual 

 that there is little or no chance for shrinkage, while the al- 

 cohol afterward helps to keep the salt in place if kept in the 

 dark (Virchow). The alba and cinerea are quite markedly 

 differentiated ; and there always exists the abnormal but char- 

 acteristic chromic color. 



An ideal preservative would be one of about the same 

 specific gravity as the brain itself, replacing gradually the 

 natural fluids of the tissue with a simple fluid, or with a solu- 

 tion of some salt of equal density, and not markedly chang- 

 ing the natural color or size of the specimeti. 



