TEMPERATURE AND HUMIDITY 



77 



climates and should be carefully combated by drinking a sufficiency 

 of watery fluids because of the danger of lithiasis. 



Effect on the Generative Organs. — The generative organs act more 

 vigorously in the tropics, but venereal excess is distinctly more 

 deleterious than in the Temperate Zone. 



Menstruation begins about one year earlier in European girls living 

 in the tropics than in those living in the Temperate Zone. For 

 instance, it begins in 48-4 per cent, at thirteen to fourteen years of 

 age, and in 50-07 per cent, at fifteen to sixteen years of age. 

 Eurasian and East Indian girls, according to Das, mostly begin to 

 menstruate at thirteen years (54*8 per cent.), though a considerable 

 number do so at twelve years (18 -6 per cent.). Natives of India 

 mostly begin about eleven to twelve years of age (63-51 per cent.), 

 and high-caste Indian girls begin in their eleventh year (50 per cent.) 

 or twelfth year (48 per cent.); but this early menstruation may be 

 associated with child-marriage rather than climate. Puberty in 

 boys appears at an earlier age than in temperate climates. 



There appears no reason to doubt that the climacteric is a more 

 trying time for the European woman in the tropics, and tends to 

 produce neurasthenia. If possible, therefore, such a woman should 

 be sent to the Temperate Zone during this period. 



It is possible that fertility is not affected in Europeans, though 

 there is some doubt on this subject, and evidence is increasing that 

 it greatly decreases after the second or third generation. Abortions 

 are said to be more common in the European in the tropics than in 

 the Temperate Zone, and post-partum haemorrhage is also said to 

 be more common, but these statements require careful investiga- 

 tion before being accepted. 



Effect on Growth. — Rattray made observations on the weight 

 and growth of forty-eight naval cadets, aged from fourteen and a 

 half to seventeen years, during four successive changes of climate 

 during a voyage. He considered that they grew too rapidly and 

 lost weight considerably in the tropics, and that their strength and 

 health was impaired by the heat. 



These conclusions of Rattray's are of the greatest importance, 

 showing clearly the necessity (well known) of sending European 

 children as soon as possible to live in the Temperate Zone, not 

 merely, as some writers assert, for education, but, much more 

 importantly, for their health. 



Effect on the Skin. — ^The cutaneous system in all tropical regions 

 is flushed with blood, and in the damper parts is more or less covered 

 with visible sweat, which is apparently suitable for the growth of 

 fungi. 



In the dry hot climates the skin is dry, and in persons who possess 

 few layers of horny cells it is liable to become inflamed and cracked. 

 The hair, particularly on ladies who have resided some time in the 

 dry tropics without a change, is apt to fall out. 



