BRAINS AND BRAIN PRESERVATIVES— HRDLWKA. 



251 



may be that of species, which opens a large field of inquiry. But, in 

 other instances, members of the same species, and that even wheri 

 collected and preserved under nuich the same conditions, show pro- 

 nounced ditferences, and these can hardly be accounted for on other 

 basis than chemical. The following- figures show two such instances, 

 (1) in human and (*2) in bear's brains: 



X ^ j: 



A=brain of a full-l>loocle(l iio^cro wDiiian. Received Oet. 0. Iit0:i. OriKinal weight l.dOG grains. 



B=brain of a mixed-blooded (about ^ white. X negro) woman. Received Oct. 14. 11)03. Original weight 1,106 grams. 



Fig. 1.— Curves showing differences in weight changes of two human brains in 5 per cent 



formalin solutions. 



The principal source of chemical difi^'erence between brains capa- 

 ble of aft'ecting their behavior in preservatives is, undoubtedly, 

 decomposition. Concerning individual or perhaps even racial chem- 

 ical diflerences in the organ, before decomposition, there is as yet no 



s a 



120 rt rt 



per cent r r i ' ! 



A, Cat. No. 224387, U.S.N.M., Vrsus torquatus. B, Cat. No. 22438C, U.S.N.M., Ursiis torquatns. 



Fig. 2.— Curves showing differences in weight changes of two bear brains in a per c'ent 



FORMALIN SOLUTION. 



knowledge. The subject presents an attractive and important field 

 for investigation. 



The behavior of the brains of the young difiers, in general, from that 

 of the adults in the various solutions. Most of the young show a greater 

 initial increase in weight and all sufler a greater eventual loss (see fig. 3). 



