ABSORPTION BY THE SKIN ETC. 287 



min (1863), it was shown that water is absorbed in a bath, and that various 

 medicinal substances may be taken up by the skin in this way and can be 

 detected afterward in the urine. 



It has been frequently remarked that the sensation of thirst is always least 

 pressing in a moist atmosphere, and that it may be allayed to a certain extent 

 by baths. It is true that in a moist atmosphere the cutaneous exhalations 

 are diminished, and this might account for the maintenance of the normal pro- 

 portion of fluids in the body with a less amount of drink than ordinary ; but 

 one could hardly account for an actual alleviation of thirst by immersion of 

 the body in water, unless it were assumed that a certain quantity of water 

 had been absorbed. A striking example of relief of thirst in this way is given 

 by Captain Kennedy, in the narrative of his sufferings after shipwreck, when 

 he and his men were exposed for a long time without water, in an open boat. 

 With regard to his sufferings from thirst, he says : " I can not conclude without 

 making mention of the great advantage I derived from soaking my clothes 

 twice a day in salt-water, and putting them on without wringing. . . . There 

 is one very remarkable circumstance, and worthy of notice, which was, that 

 we daily made the same quantity of urine as if we had drunk moderately of 

 any liquid, which must be owing to a body of water absorbed through the 

 pores of the skin. ... So very great advantage did we derive from this 

 practice, that the violent drought went off, the parched tongue was cured in 

 a few minutes after bathing and washing our clothes ; at the same time we 

 found ourselves as much refreshed as if we had received some actual nour- 

 ishment." 



Absorption by the Respiratory Surface. Animal and vegetable emana- 

 tions may be taken into the blood by the lungs and produce certain well 

 marked pathological conditions. Many contagious diseases are propagated 

 in this way, as well as some fevers and other general diseases which are not 

 contagious. With regard to certain poisonous gases and volatile matters, 

 the effects of their absorption by the lungs are even more striking. Carbon 

 monoxide and arsenious hydride produce death almost instantly, even 

 when inhaled in small quantity. The vapor of pure hydrocyanic acid acts 

 frequently with great promptness through the lungs. Turpentine, iodine 

 and many medicinal substances may be introduced with great rapidity by in- 

 halation of their vapors ; and the serious effects produced by the emanations 

 from lead or mercury, in persons who work in these articles, are well known. 

 Not only have vapors introduced in this way been recognized in the blood, 

 but many of the matters thus absorbed are excreted by the kidneys and may 

 be detected by their characteristic reactions in the urine. 



As would naturally be expected, water and substances in solution, when 

 injected into the respiratory passages, are rapidly absorbed, and poisons ad- 

 ministered in this way manifest their peculiar effects with great promptness. 

 Experimenters on this subject have shown the facility with which liquids 

 may be absorbed from the lungs and the air-passages, but it must be remem- 

 bered that the natural conditions are never such as to admit of this action. 

 The normal office of the lungs is to absorb oxygen and sometimes a little ni- 



