PERSPIRATION. 231 



escape from the surface of the skin by mere exhalation and trans- 

 udation are far more important as excretions than the actual ele- 

 ments of the perspiration. It is, therefore, probably because the 

 action of the skin as an exhaling and transuding surface is suddenly 

 checked, and not that of the perspiratory glands alone, that such 

 serious consequences ensue from such sudden changes. It is far 

 more because carbonic acid and nitrogen gases, and water also, cease 

 to be given off, than because the perspiratory elements and the 

 minute amounts of the acids of the sweat are still retained in the 

 blood, that the mischief results. And it is not singular that the 

 pulmonary surface, or that of the alimentary canal, or of the urini- 

 ferous tubes, should manifest a higher amount of power as a trans- 

 uding surface when thil physical process is suddenly checked on 

 the skin; and that catarrhs, diarrhoeas, or diuresis should result 

 therefrom. 



