244 STUDY OF BRAINS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 



I have attempted to justify my belief by calculations based on a comparison of 

 the present weights and dimensions of the two Leidy brains, assuming that, inasmuch 

 as the two men died practically together and the brains were subjected to very sim- 

 ilar conditions of preservation and have lain immersed in like fluids for eqiial periods 

 of time, any errors involved and allowances called for must be really very trifling. 



I. 



The present weights of the encephalic parts of the two Leidys are as follows : 



Joseph Leidy. Philip Leidy. 

 Left hemicerebrum ....... 565 525 



Right hemicerebrum ...... 595 522 



Cerebellum 128] 



,165 162 



Pons and oblongata ...... 37 



1325 1209 



A glance will show that while the weight of the isthmus and cerebellum is almost 

 alike in the two brains, there is a material difference between the weights of the 

 cerebral parts. • 



II. 



Now assuming Philip Leidy's original brain-weight (1415 grams) to have been 

 correct, we have : 



1209 : 1415:: 1325 :x. 



The value of x is, therefore, 1550. 



Again, multiplying the present figures of the weight of Philip Leidy's hardened 

 brain by (approximately) 1.16 in order to obtain the original weights, we have : 



Left hemicerebrum ....... 615)^, 



\ Cerebrum 1226 

 Right hemicerebrum ...... 610 J 



Cerebellum, pons and oblongata .... 190 



1415 grams 



Endeavoring now to arrive at the weight of Joseph's cerebrum, we have : 



1047 : 2125:: 1160 :.r. 



The value of x is, therefore, 1356. 



This leads us to assume that Joseph Leidy's brain must have weighed : 



Left hemicerebrum ........ 660 



Right hemicerebrum ........ 690 or more 



Cerebellum, pons and oblongata ...... 195 



Approximately 1550 grams 



