Donaldson, Growth of Central Nervous System. ^^y 



As in the case of the brain, however, it seems justifiable to treat 

 the sexes together. When so treated, the theoretical curve as 

 shown by the continuous line (C) in chart 3 is found by the 

 formula [3] 



y = -585 (^ + 21) -0.795 



in which y is the weight of the spinal cord and x the body weight. 



This formula [3] was derived in the same manner as formula [i]. 

 The means for the weight of the spinal cord, determined as in 



the case of the brain, follow this curve closely (see chart 3). The 



nH. 



pinal 

 .8564 

 f the 

 body 

 CORRECTION. opos 



On* page 357 of The Jourxal of Comparative 



Neurology and Psychology, Vol. XVIII, No. 4, , , 



1908, Fonimla (3) is erroneously printed , 



y = .585 (x + 31) — 0.795. ^^ ^" 



•^ \ I / ance 



The correct form is apid 



y = .585 Log (x + 21) — 0.795. in a 



i far 

 viest 

 ; the 

 isive 

 the 



_ ^ J3 j5 ,- -" -.v-.*v.ix^v*, Yviiv^ii Liic vdiucs on tne logarrtTimic 



curve and those determined by the 2.7th root of the body weight 

 become identical. As in the case of the brain, we consider this 

 point of intersection of the two lines to mark the cessation of rapid 

 growth. As far down as the 205 gms. group, then, the weight 

 of the spinal cord is in a simple relation to that of the body weight. 

 Using this fact as a criterion, we may look upon the earlier growth 

 of the spinal cord up to the 205 gms. group as rapid, while after 

 that it is slow. 



As in the case of the brain, so in the spinal cord, the varia- 

 tions in the growth of the body which produce "giants" or 

 "dwarfs," or the stunting which may be brought about experi- 



