,430 PHYSIOLOGY. 



troubles, the most remarkable of which is the cooling of the body. 

 This cooling is due to vasodilatation, and is the cause of death. 



There seems to be a very steady relation between the amount of 

 moisture exhaled from the lungs and the secretion of sweat. It is 

 calculated in general that the perspiration is double that of the 

 water from the lungs and, on an average, is one sixty-fourth of the 

 weight of the body. 



Suppression of Sweat by Cold, All pathologists recognize cold 

 as the cause of many lesions of an inflammatory nature. If this be 

 true, it is produced not by suppression of sweat alone. It is prob- 

 able that there is a transmission of impressions by the skin-nerves 

 to the nerve-centers. These impressions generate, by an obscure 

 pathogenic mechanism, probably bacterial, the inflammations of the 

 viscera. 



Bole of Sweat-secretions. The sweat is an important means for 

 the elimination of water and alkalies. 



It is also of very great use in the excretion of fatty volatile acids 

 introduced into, or formed in, the organism. It is able to supple- 

 ment the urinary secretion, for the skin is vicarious for the kidneys. 

 It also carries off medicines and poisonous principles. It regulates 

 animal heat, since the evaporation of the water of sweat cools the 

 body. The secretion of sweat is independent of the circulation ; how- 

 ever, there exists a relationship between them. Thus, an abundance 

 of sweat requires a full, free circulation. As the salivary glands need 

 a flow of blood to furnish materials for secretion, so do the sweat- 

 glands. 



I have shown elsewhere that the sudorific centers are in the 

 spinal cord and that their fibers run in the lateral columns. The 

 sweat-centers are excited by an excess of C0 2 in the blood and by over- 

 heated blood. Camphor, acetate of ammonium, and pilocarpine ex- 

 cite sweat by a direct action on the centers. Muscarine excites sweat 

 by a local action; atropine arrests it. 



Pathological. Besides the components mentioned, biliary pig- 

 ment is also found in the sweat of persons having jaundice; sweat 

 becomes bitter after strong doses of quinine from its appearing in 

 this medium during its elimination from the body. The sweat of 

 diabetes is found to be sweetish, although the presence of glucose in 

 it has not been definitely determined. The red pigmentation some- 

 times found is attributed to the blood-globules, crystals of which 

 were found in the sweat. Hebra saw it succeed menstruation; but 

 it may also occur in serious nervous disease and in yellow fever. In 



