16 FREER. 



inations give protocols clearly pointing to heat stroke. Monkeys 

 enclosed in tight boxes, with only the head exposed, and placed 

 in the full sun, suffer no inconvenience, although the hair tem- 

 perature on the scalp may reach 47°. The effects, therefore, are 

 not due to penetration of the sun's rays to the brain. Of course, 

 it must be understood that the monkey's skin is protected by 

 fur and is not sensitive to the irritating effects of the ultra- 

 violet rays, such as would be the skin of a Caucasian^^ who, 

 as we all know, if exposed to the sun, would be sunburned, 

 whether in a strong blast of air or not. This latter effect 

 is due to the ultra-violet portion of the spectrum, and as the 

 latter rays have but little power of penetration the skin can 

 in time amply protect itself by pigmentation. Even though 

 pigmented, as is the monkey's skin and hence not subject to 

 sunburn, the heat effect would still remain and bring about the 

 results of excessive heat exposure in exactly the same manner 

 as in the case of the monkeys. The ultra-violet rays are easily 

 guarded against, the heat rays not. 



Experiments on man exposed to the sun are equally interest- 

 ing. In man we have a subject with highly developed sweat 

 glands, so that the means of heat regulation by evaporation are 

 much more complete than in dogs, rabbits, or monkeys. 



Skin temperatures of men in this climate in the shade under 

 normal conditions vary, as measured by the apparatus con- 

 structed in Manila, within the extreme limits of 31° to 34°, 

 being higher over the muscular and fatty parts of the body than 

 over bony structures' lying close to the surface. These varia- 

 tions must be considered and therefore measurements on the 

 changes of temperature, when exposures are made, must be 

 taken at various points of the body. 



After ten to fifteen minutes' exposure to the sun, the skin 

 temperature of an American subject, on the sunny side, rose 

 to 35°. 8, 35°.2, and 41°. 8 on the arm, cheek, and chest in the 

 order named, whereas on the shaded side these temperatures 

 were 31°. 5 and 31°. 9 on the first two; the hair temperature 

 rose to 46°. The corresponding temperatures in a Filipino, 

 after thirty minutes, were 36°.9, 35°.4, and 39°.8, the shade 

 temperatures being 32°. 5, 31°.9, and 32°. 5 the differences 

 being, in regard to the brown skin, +1°.!, 4-0°-2, and —1°. 

 A comparative measurement of an American and Filipino, side 



" Aron exposed a shaved monkey. It died within one hour, with the 

 same autopsy protocol as others. Its temperature rose more rapidly than 

 that of the others, reaching 45°. 5 and 44°. 4. 



