igS Journal of Comparative Neurology. 



the reactions of the entire frog toward water, the conditions 

 which distinctly modify this process are: (i) The amount of 

 water in the body of the frog — the increase in the absorbing 

 cord being less when the frog is dry ; (2) The length of time 

 during which the absorbtion is allowed to continue — the 

 increase in the absorbing frog being greater the longer the 

 time. (These observations do not extend beyond twenty-four 

 hours.) (3) Finally, the weight of the frog is a factor; the 

 larger frogs showing the greater relative increase in weight of 

 the absorbing cord. On extending these observations, we 

 have a few cases to show that in the bull-frog, a similar increase 

 in the weight of the cord occurs after death, but in the mature 

 white rat there is no evidence that this reaction occurs. 



BIBLIOGRAPHY. 



189S. Observations on the Weight and Length of the Central Nervous 

 System and of the Legs in Bull-Frogs of Different Sizes. — By Henry 

 H. Donaldson, Journ. of Comp. Neurology, Vol. VIII, No. 4, Dec. 

 See page 318. 



1900. Observations on the Weight and Length of the Central Nervous 

 System and of the Legs in Frogs of Different Sizes (Rana virescens 

 brachycephala Cope). — By Henry H. Donaldson and Daniel M. 

 ScHOEMAKER, Journ. of Comp. Neurology, Vol. X, No. i, February. 

 See page 1 16. 



