282 PERSPIRATION. 



He did not find moist cold air to cool animals more than dry 

 cold air. 



In low temperatures, we have seen that the loss by evaporation 

 greatly exceeds that by secretion. In high, it is the reverse ; 

 and, when the body is covered with sweat, there can be no loss 

 by the evaporation which occurs, independent of secreted fluid, 

 whether the air be dry or moist. Vapour will cause more loss by 

 secretion than dry air ; but no loss can take place by the lungs in 

 hot vapour. x 



Perspiration can never be entirely suppressed; because the 

 cold which suppresses secretion, causes the air, however moist, 

 and therefore opposed to evaporation, to rise in temperature, by 

 coming in contact with the body ; and the superior temperature 

 which it instantly acquires, enables it to hold more moisture, and 

 evaporation from the skin is thus instantly promoted, y 



There is a common belief, that the cutaneous exhalation has 

 always peculiar properties, invigorating in the young, and debili- 

 tating in the old. David lay between two young girls to gain 

 strength ; and Dr. Copland declares he has seen a child suffer from 

 lying with its grandmother. 2 



The elimination of foreign matters by the skin is shewn by the 

 odour of the perspiration after some odorous substances have 

 been taken, by its effect upon silver when mercury is prescribed, 

 and by its green and coppery secretion when copper has been in- 

 troduced. a 



The odour of the secretion of the sebaceous follicles, and that 

 of the perspiration, are, in some parts, naturally peculiar, and 

 in different persons more or less intense, and even singular; 

 and either always, only under excitement, or only at times 

 when under excitement, in different parts. In the tonsils, 



x p. 380. sq. y p. 335. sq. 



z Dictionary of Practical Medicine, by James Copland, M.D., art. DEBILITY. 

 A work displaying such extraordinary extent of reading, and such deep and 

 comprehensive reflection, as to demand a place in the library of every medical 

 man. 



a See a case in the Land. Med. Gazette, Nov. 19. 1832. 



" Hence the danger of contagion from hairs, as miasmata adhere to them very 

 tenaciously for a great length of time. Vide Cartwright, Jbumalof Transactions 

 on the Coast of Labrador, vol. i. p. 273. vol. ii. p. 424." 



" G. Wedemeyer, Historia Pathologica Pilorum (honoured with the royal 

 prize). Getting. 1812. 4to." 



