SWEAT. 377 



appears in small drops in the excretory tubes. In general, 

 however, the perspiration remains in the furfuraceous layers, 

 and thus gives rise to the moisture of the skin. 



This humid condition of a superficial porous 1,'iyer places 

 the skin and the entire organism in a peculiar state : tl.e loss 

 of heat, which is in exact proportion to the abundance of the 

 perspiration, produces constant evaporation. The human 

 body resembles, in this respect, those porous vases, or alca- 

 zaras, which are used to cool water by means of the evapor- 

 ation which takes place on their surface: as sudation is 

 generally increased by the elevation of the external temper- 

 ature, or by any exertion (muscular labor) which has a 

 tendency to produce heat in the body, we possess a means of 

 defence against any too great accumulation of caloric; we 

 have seen, indeed, in our study of animal heat, that our tem- 

 perature cannot, without danger, go beyond 40 or 43 degrees 

 (C.) (see p. 343). While, however, the perspiration forms 

 a valuable aid in resisting heat, it also renders us liable to a 

 great danger, as any excess or derangement is followed by a 

 chill. 



When such a chill takes place, the secretion of the perspir- 

 ation ceases suddenly; this, however, usually happens too 

 late, and the harm is done : these chills produce extremely 

 serious and varied effects on all the parts of the organism. 

 In olden times the arrest of sudation was looked upon as the 

 most important part of the whole process, and perspiration 

 was looked upon chiefly as an emunctory; its suppression 

 was considered the retention of poisonous materials. Ihe 

 perspiration, no doubt, contains excreta, but not, it would 

 seem, in sufficient quantity to produce blood poisoning, and 

 while we consider the cooling effect as the principal physiolog- 

 ical office of the perspiration, we look upon any exaggeration 

 of it as the chief cause of some derangements in which the 

 suppression of the perspiration is only a concomitant phe- 

 nomenon. One of the first effects that follow this cooling is 

 invariably a change in the blood, the fibrine of which in- 

 creases; this may perhaps be owing to some derangement 

 in the condition of the deep layers of the epidermis, as, in- 

 deed, in such cases, ganglionic swellings are often observed, 

 the suffering or agony of the epidermis being, as it were, 

 transmitted to them by means of the lymphatic vessels. Dr. 

 Lang (of Gottingen), however, by studying the effects pro- 

 duced from suppression of cutaneous perspiration, has obtained 

 the following results: on making the autopsy of animals 



