280 PERSPIRATION. 



15 oz., and the cutaneous to 30 oz. The quantity of carbon se- 

 parated by the lungs ought however to be taken into the account. 

 If it amount to 11 oz. in twenty-four hours, the quantity stated 

 by Allen and Pepys there will be but 4 oz. of pulmonary ex- 

 halation. But if oxygen and azote are absorbed in respiration, 

 there must have been correspondently more pulmonary exhalation ; 

 and we have seen that Hales estimated it at about 20 oz. in the 

 twenty-four hours. They found the cutaneous transpiration at 

 its minimum during and immediately after meals, and at its max- 

 imum during digestion. 



The minimum after digestion was found by them to be 11 grs* 

 per minute ; the maximum 32 grs. : at and immediately after dinner 

 lO^o ; and the maximum 19 T ^, under the most favourable and un- 

 favourable circumstances. It was increased by liquid, but not by 

 solid, food. The pulmonary they regard as greater than the cu- 

 taneous, proportionally to the surface on which it occurs. What- 

 ever was taken, the weight was found to become ultimately as 

 before. Indigestion lessened transpiration, and the body con- 

 tinued heavier generally till the fifth day, when the original weight 

 was restored. Transpiration was less in moist air and at a low 

 temperature, and the pulmonary and cutaneous transpirations 

 obeyed the same laws. 



Dr. Edwards has made a great number of experiments upon 

 this subject.? He distinguishes the loss of fluid by evaporation 

 of what is exuded, from that by secretion. <i The former occurs 

 even in the dead body, and is increased in both the dead and 

 living, and among all animals, by the dryness, motion, and dimi- 

 nished pressure of the atmosphere. It may be suspended by 

 saturating the air with moisture, and by employing animals (ver- 

 tebrated, cold-blooded) whose temperature is not above that of 

 the atmosphere ; for, if those are employed whose temperature 

 exceeds that of the atmosphere, the air as soon as it touches them 

 is rarified, can take up more moisture, and is no longer air satu- 

 rated with moisture. These circumstances, of course, affect only 

 the removal or evaporation of fluid which may have either trans- 

 uded or been secreted; but do not affect the secretion. In frogs, 



Annales de Chimie, t. xc. 

 P 1. c. part iv. c. xi. 



> He contends, however, that, in the lungs, all is evaporation without secre- 

 tion. But, with Dr. Bostock, I must dissent from him. 



