14 The Philippine Journal of Science 1917 



there is a marked difference in the effects of the climate of 

 Manila on different days; (2) that the maximal normal temper- 

 ature of this monkey is probably not below 39.5° ; (3) that this 

 monkey had acquired increased power of resistance to the tro- 

 pical climate at its worst; (4) that the acclimatization was 

 probably most rapid in the first two days; (5) that the acclima- 

 tization probably did not approximate completion much before 

 the end of two months' exposure; (6) that an acclimatized 

 monkey may show no discomfort in the sun of Manila even 

 when sitting on the hot roof during the hottest days of the 

 year; (7) that the temperature of an acclimatized monkey sitting 

 on a bare, hot asphalt roof day after day in the hottest portions 

 of the year in Manila may not rise above its maximal normal 

 temperature (39.9°) oftener than once or twice a month; and 

 (8) that the sun's rays alone probably have no injurious effect 

 upon the monkey. 



ACCLIMATIZED MONKEYS COMPARED WITH UN ACCLIMATIZED 



Although the comparison of the behavior of monkey 4 in 

 the sun with the behavior of the monkeys studied by Aron seems 

 to prove the acquirement of greatly increased resistance by the 

 former, the data were too few to be conclusive, and it was 

 necessary to expose it and other monkeys that had been exposed 

 to the sun alongside of monkeys that had not been so exposed. 

 Table IX gives the results of exposure to the sun and in contact 

 with roofs of acclimatized monkeys alongside of unacclimatized. 



It is readily seen from the facts shown in Table IX: (1) 

 that the unacclimatized monkeys placed in the sun in contact 

 with the hot roof may die in from forty minutes to six hours, 

 depending upon the individual resistance and upon the climatic 

 factors obtaining; (2) that ten exposures to the sun produced 

 greatly increased resistance to the sun, but were not always suffi- 

 cient to produce thorough acclimatization; (3) that twenty-one 

 exposures produced a high degree of immunity if not thorough 

 acclimatization; (4) that the temperature of an acclimatized 

 monkey rarely exceeds the maximum normal temperature, even 

 when exposed to the combined action of the sun and the hot 

 roof; (5) that sickness reduces the resistance to heat or to heat 

 combined with other climatic factors (see monkey 14, April 26) ; 

 (6) that exposure in contact with the hot ground or roof may 

 prove rapidly fatal when exposure 1 meter above the roof pro- 

 duces no symptoms (see monkeys 16 and 19, March 8 and 12), 

 that is, much the greater portion of the injury to monkeys ex- 

 posed as Aron exposed them seems to be due to the heat from 

 the roof rather than to the sun's rays. 



