STUDY OF THE EFFECT OF TROPICAL SUNLIGHT. 



101 



within too wide limits. My measurements were made with the 

 thermocouple employed by Aron ; which, however, is a different 

 one from that used in the skin measurements. The results are 

 recorded in the following table: 



'Pahlk VI. — TeiiiperaiureH in hair. 



Subject. 



Date. 



Time. 



Tempt 



rature. 





Sunny 

 aide. 



Shady 

 side. 



Rnmarks. 



Gil. P'ilipini). SittinK in chair in 



Apr. 29. 1911 



9.87 



44.5 



36.4 





sun. Thick, coarse, black hair. 













K. American. Fine, thin, silvery- 



do 



9.41 



•.50.1 



36.7 





white hair. Sitting in chair in 













sun. 













G. American. Thick, brown hair. 



do 



10.40 





3;j.45 



In shade under hat. 



SittinK totiilly in shade. 













F\ American. Totally in shade 



do 



10.45 







34.05 



In shade under hat. 



Ros. Filipino. Thin, black hair. 



May 3. 1911 



10.00 



39. 2 



34.1 



Subject perspirinc 



SittinK in chair in sun. 











freely where hair 

 is quite thin. 



Rey. Filipino. Thick, coarse, black 



May 4.1911 



10.30 



45.5 



36. 1 



BriKht sun. 



hair. SittinK in chair in sun. 













M. American. SittinK in chair in 



do 



10.35 



46.4 



- - 





sun. Thin, liKht brown hair. 













Gil. (See above) 



do 



10.40 

 11.00 



41.5 

 37.6 



32.2 





E. American. Hair, dark brown . . 



do 



After running ex- 













ercise, almost no 













visible perspira- 













tion. 



Ros. (See above) 



do 



11.10 



40.0 





After running ex- 







ercise perspiring 













freely. 



Alipet. iKorot. Thick, coarse. 



May 17,1911 



9 



35.3 



34.1 





black hair. 













MaK«mba. Igorot. Coarse, black 



...do 



9.10 



42.3 



32.8 





hair, thinner than last. 













* This value is remarkably high, due to the fact that the subject has silvery-white hair 

 which is rather thin and affords insufficient protection. The thermocouple, even though 

 it was so buried in the hair as to be invisible, absorbed a considerable amount of heat by 

 direct radiation. 



In the consideration of the skin temperatures of human beings 

 it must be remembered that the number of sweat glands, the 

 thickness of the subcutaneous fat layer and especially the sen- 

 sitiveness of the vasco-motor apparatus, certain sub.iects flushing 

 under much weaker stimulus than others, are factors which 

 must be excluded by experiments upon a large number of subjects 

 before the influence of pigmentation can be determined. My 

 experiments are not suflficiently extensive to warrant the drawing 

 of general conclusions. 



