BRAIN WEIGHT 



207 



milligram. The values for the graph, males only, in chart 30 

 and for table 144 were computed by formula (13), corrected for 

 sex. Donaldson ('08), ('09); Hatai, ('09a). 



For convenience the graph for the spinal cord is given on the 

 same chart as that for the brain. The graph for the male only 

 is entered. For the same body length as the male the spinal 

 cord in the female is about 5 per cent heavier, and for the same 

 body weight, about 2 per cent heavier. Donaldson ('08, '09); 

 Hatai ('09 a). 



Chart 30 Giving the brain weight on the body weight. Males only. Formu- 

 las (9) and (10), table 144. Also spinal cord weight on the body weight. Males 

 only. Formula (13), table 144. 



Weight of parts of the hrain. The change in the weight of the 

 parts of the brain has been reported by Sugita ('17) table 140. 



Technic: The olfactory bulbs were severed by a shghtly 

 obhque cut just caudad to the gray cap. The cerebellum was 

 separated by section of the peduncles close to the stem. The 

 stem was divided from the cerebrum by a section cephalad to 

 the anterior quadrigemina. 



Weight of both eyeballs on body weight. Technic: Care being 

 taken to remove the muscle attachments, both eyes were weighed 

 in a closed weighing bottle. The graph is based on rats studied 



