258 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXX. 



TEN PEK CENT AND 15 I>ER CENT FORMALIN SOLUTIONS. 



In these the number of mammals was rather small and all were of 

 small size, which had an effect on the figures. All the specimens 

 increased in weight, as in the 3 per cent and 5 per cent formalin solu- 

 tions during the early part of the first month, and slowly and con- 

 tinuously declined afterwards. The ultimate weight reached was in 

 eyery case, and particularly in the 15 per cent liquid, lower than with 

 the weaker solutions. It was greater in the birds than in the mammals^ 

 Experiments on the larger and more uniform brains of sheep showed 

 plainly a progressiyely less initial augmentation and lower subsequent 

 fall in weight with the increase in strength of the formalin to 10 and 

 15 per cent. 



l.im) AND 1,035 SPECIFIC GRAVITY SALT SOLUTIONS, WITH 5 PER CENT FORMALIN. 



These two solutions acted practically alike; the 1,030 sp. gr. liquid 

 was more largely used, for the reason that fewer brains will float in it. 



XXi- 



90 per cent. 



l 



I .; 



70 per cent. 



4-4-^ 



■■■■ , T- T "7 



ft 



Mammals, adult, Bird.s, adult 



Fig. 8.-CURVES showing changes in brain weights in 1,030 specific gravity salt formalik 



SOLVTION. 



Only adult mammal and bird brains were preseryed in the solution, no 

 normal human or 3'oung specimens haying reached the laboratory 

 while it was being employed. A large majority of brains in both 

 series showed at the end of the first week a decided loss in weight, 



