CORRELATION OF BRAIN AND SPINAL CORD. 523 



This generally lesser variability of the central nervous system 

 is a demonstration that it is much more metabolically stable than 

 are the other organs of the body so far studied. The interpreta- 

 tion is based on the difference in chemical make-up already 

 discussed, in which differences in type metabolism participate. 

 A more extended discussion of the problem is reserved for a 

 later paper. 



SUMMARY AND CONCLUSIONS. 



The brain and spinal cord of the albino rat show a high degree 

 of positive weight correlation, free from the influences assumed to 

 be exerted by the other variables studied (body weight, body 

 length). The value for the male is 0.567, and for the female 

 0.570. 



The weight variability of the brain and spinal cord is less than 

 that of any of the other organs so far studied. It is greater than 

 that of the body in length. 



The analysis and interpretation of these and other relations 

 are given in detail in the text. 



The computations upon which this study is based were made by 

 Miss Mildred Wilson. 



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