yS Society for Experimental Biology and Medicine. 



will develop, many or possibly the majority of the eggs that have 

 in addition been exposed to the hyperalkaline solution will develop 

 into larvae many of which are perfectly normal and rise to the 

 surface. I have further found that the eggs which develop into 

 larvae very often (possibly always) have a membrane which, how- 

 ever, differs from the fatty acid membrane or the fertilization mem- 

 brane in this, that it is not separated by so wide a space from the 

 protoplasm and therefore easily escapes detection. 



In a former paper I have already pointed out that the facts of 

 natural fertilization agree also with the view set forth in the 

 introductory remarks of this note. 



53 (10) 



Comparative chemical composition of the hair of 

 different races. 



By THOMAS A. RUTHERFORD and PHILIP B. HAWK. 



\From the Laboratory of Physiological Chemistry of the Department 

 of Medicine of the University of Pennsylvania^ 



Forty-five samples of hair were analyzed, the specimens being 

 obtained from indian, negro, japanese and Caucasian subjects. 

 After subjecting the hair to the action of digestive juices and 

 alcohol and ether the percentage content of sulphur, nitrogen, 

 carbon and hydrogen in the remaining keratin was determined. 

 The analyses indicate that the chemical composition of human hair 

 is influenced by six factors, as follows : (1) Race of the subject; 

 (2) sex of the subject ; (3) age of the subject ; (4) color of the hair ; 

 (5) purity of breeding of the subject ; (6) whether the hair sample 

 is obtained from a dead or living subject. 



The average percentage composition of the forms of hair 

 (keratin) analyzed is given below. 



Subject. Elementary percentage composition. Ratio. 





s 



N 



c 



H 



O 



S :N 



Indian 



4.82 



15.40 



44.06 



6-53 



29.19 



I : 3 .2 



Japanese 



4.96 



14.64 



42.99 



5-91 



31-50 



I :3-0 



Negro 



4.84 



14.90 



43-85 



6.37 



30.04 



1:3-1 



Caucasian : 















Adults 



5.22 



15.19 



44-49 



6.44 



28.66 



I : 2.9 



Children 



4-93 



14.58 



43- 23 



6.46 



30.80 



1:3.0 



