ABSORPTION BY THE SKIN. 347 



tied and cut out, about a quarter of a cubic inch of carbonic 

 acid gas was exhaled by the skin in eight hours. And this 

 quantity is very large, when it is remembered that a full-sized 

 frog will generate only about half a cubic inch of carbonic 

 acid by his lungs and skin together in six hours (Milne- 

 Edwards and Miiller). That the respiratory function of the 

 skin is, perhaps, even more considerable in the higher animals 

 than appears to be the case from the experiments of Regnault 

 and Reiset just alluded to, seemed probable by the fact ob- 

 served by Magendie and others, that if the skin of animals is 

 covered with an impermeable varnish, or the body inclosed, 

 all but the head, in a caoutchouc dress, animals soon die, as if 

 asphyxiated ; their heart and lungs being gorged with blood, 

 and their temperatures, during life, gradually falling many 

 degrees, and sometimes as much as 36 F. below the ordinary 

 standard (Magendie). Some recent experiments of Lashke- 

 witzch appear, however, to confirm the opinion of Valentin, 

 that loss of temperature is the immediate cause of death in 

 these cases. A varnished animal is said to have suffered no 

 harm when surrounded by cotton wadding, but it died when 

 the wadding was removed. 



Absorption by the skin has been already mentioned, as an 

 instance in which that process is most actively accomplished. 

 Metallic preparations rubbed into the skin have the same 

 action as when given internally, only in a less degree. Mer- 

 cury applied in this manner exerts its specific influence upon 

 syphilis, and excites salivation ; potassio-tartrate of antimony 

 may excite vomiting, or an eruption extending over the whole 

 body ; and arsenic may produce poisonous effects. Vegetable 

 matters, also, if soluble, or already in solution, give rise to 

 their peculiar effects, as cathartics, narcotics, and the like, 

 when rubbed into the skin. The effect of rubbing is probably 

 to convey the particles of the matter into the orifices of the 

 glands whence they are more readily absorbed than they 

 would be through the epidermis. When simply left in con- 

 tact with the skin, substances, unless in a fluid state, are sel- 

 dom absorbed. 



It has long been a contested question whether the skin 

 covered with the epidermis has the power of absorbing water ; 

 and it is a point the more difficult to determine because the 

 skin loses water by evaporation. But, from the result of 

 many experiments, it may now be regarded as a well-ascer- 

 tained fact that such absorption really occurs. M. Edwards 

 has proved that the absorption of water by the surface of the 

 body may take place in the lower animals very rapidly. Not 

 only frogs, which have a thin skin, but lizards, in which the 



