7 lie Relative Size of Red- Blood Corpuscle and Brain. 27 



THE RELATIVE SIZE OF RED-BLOOD CORPUSCLE AND 



BRAIN. 



Bv B. Merrill Ricketts, M. D. 

 {Read January 4, 1887.) 



After spending considerable time in looking over the literature 

 and comparing the weights of the brain, size of red corpuscles and 

 nerve tubes, as found in each of the four divisions of the sub-king- 

 dom Vertebrata, I am led to believe that there exists some special 

 relation between them. 



We have to consider the relation: 



First : Of the red corpuscle to vital force. 



Second : Of the brain to activity. 



Third: Of the nerve tube to temperature. 



While there is a considerable amount of general literature upon 

 the habits and make-up of the animal kingdom, there is nothing 

 to my knowledge that bears directly upon the subject that I present 

 to you, consequently many points that would be of special interest 

 must be omitted. 



There are some interesting features in connection with the red 

 corpuscle, not only because it is the messenger that conveys the 

 important elements to the varioustissuesof the body, but because of 

 its J.upposed relation to force and activity as well. These are de- 

 pendent upon digestion, circulation, respiration and muscular 

 structure, and are influenced and controlled by the brain and its 

 appendages. 



There is evidence also that force and activity are influenced 

 by the relative size of the red corpuscles to the brain in general, 

 which relation is in an inverse ratio, the corpuscle being small as 

 the brain is large, both the cerebum and cerbellum tend to 

 increase in size, and become more complex in passing from fish to 

 reptiles, from reptiles to birds, and from birds to mammals ; also 

 the relative size of the brain to the body is found to vary, as does 

 the ratio of the size of the corpuscle to that of the cerebellum. 



That this ratio exists can best be shown by carefully consider- 

 ing each divison of the sub-kingdom vertebrata ; this may be done 

 more conveniently by selecting for our types, so far as previous in- 

 vestigation will allow, the largest and smallest animal of each divis- 



