PERCENTAGE OF WATER: WILD NORWAY 381 



In considering the data in table 21 1 it must be remembered that 

 while the percentage of water in the brain and spinal cord is primar- 

 ily a function of age, yet at the same time body weight is rather 

 poorly correlated with age. This certainly accounts for some of 

 the irregularities which appear in this table. 



The slightly higher percentage of water in the Norway nervous 

 system is probably due in part to the greater mass of cytoplasmic 

 substance as indicated b}- the slightly greater size of the cell bodies 

 in the Norway. 



GROWTH IN TERMS OF WATER AND SOLIDS: REFERENCES 



Refractive index of serum. Hatai, '18. 



Percentage of water in the nervous system — brain and spinal cord. Donaldson 

 and Hatai, '11. King, '23. 



