418 



THE SKIN AND ITS APPENDAGES. 



Sweat in gen- 

 eral (obtained Sweat 

 by elevation (from extremities), 

 of tempera- 

 ture). 

 Favre. Schottin. Fiinke. 



Water 995.573 977.40 988.40 



Solids 4.427 22.60 11.60 



Soluble in water : 



Sodium chloride 2.230 3.6 



Potassium chloride 0.244 . . 



Alkaline sulphates 0.012 \ 



Alkaline phosphates traces j 



Albuminates 0.005 



Insoluble in water, but soluble in acidu- 

 lated water : 



Earthy phosphates traces 



Soluble in alcohol : 



Alkaline lactates 0.317 ] 



Alkaline sudorates 1.562 ! 



Urea 0.043 [ 



Fats and fatty acids 0.014 j 



Insoluble in water and alcohol : 



Epithelium traces 4.20 



1.31 



0.39 J 



4.36 



7.24, 



11.30 }- of which 

 I 1.55 urea. 



2.49 



Gases. While in mammals and birds the respiratory function of 

 the skin is insignificant as compared with that of the lungs, we find 

 that in the amphibia life may persist for quite a while after removal 

 of the lungs, and that during this time oxygen is actively taken up 

 from the air and carbon dioxide eliminated in turn. If, however, 

 the exchange of gases is impeded or prevented by covering the 

 skin with a thin layer of varnish, death rapidly takes place. This 

 also occurs, it is true, in some of the smaller mammals which have 

 a delicate skin, but it is now known that the fatal end is here not 

 referable to the impairment of the cutaneous respiration, nor to a 

 retention of waste products, as was formerly supposed, but to a 

 paresis of the cutaneous vasomotor nerves and a resulting dilatation 

 of the bloodvessels. As a result an abnormally increased irradia- 

 tion of heat occurs, which constitutes the direct cause of death. If 

 this is prevented by placing the animal in a warm chamber or by 

 surrounding it with cotton and the like, recovery may take place. 

 In the larger mammals, including man, in which a coarser skin 

 exists, no deleterious effects are noted even after ten days. 



The amount of carbon dioxide which is given off by man through 

 the skin is principally dependent upon the surrounding temperature, 

 and varies between 8.4 grammes at 29 to 33 C., and 28.8 grammes 

 at 38.5 C. 



The Sebum. The sebum is the specific secretory product of the 

 sebaceous glands, and serves the purpose of a lubricant. Amounts 

 sufficient for analytical purposes can be obtained from newly born 

 children, in which the secretion constitutes the so-called vernix case- 

 osa. In the fresh state it is a semiliquid, oily material, in which 

 on microscopical examination can be discerned desquamated epithe- 

 lial cells in various stages of degeneration, fat droplets, fatty acid 

 needles, and quite constantly also plates of cholesterin. Almost 



