426 HANDBOOK OF PHYSIOLOGY. 



the orifices of the glands, whence they are more readily absorbed than 

 they would be through the epidermis. When simply left in contact 

 with the skin, substances, unless in a fluid state, are seldom 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-ascertained fact that such absorption really occurs. The absorption 

 of water by the surface of the body may take place in the lower animals 

 very rapidly. Xot only frogs, which have a thin skin, but lizards, in 

 which the cuticle is thicker than in man, after having lost weight by 

 being kept for some time in a dry atmosphere, are found to recover both 

 their weight and plumpness very rapidly when immersed in water. 

 When merely the tail, posterior extremities, and posterior part of the 

 body of the lizard are immersed, the water absorbed is distributed 

 throughout the system. And a like absorption through the skin, though 

 to a less extent, may take place also in man. 



In severe cases of dysphagia, when not even fluids can be taken into 

 the stomach, immersion in a bath of warm water or of milk and water 

 may assuage the thirst; and it has been found in such cases that the 

 weight of the body is increased by the immersion. Sailors also, when 

 destitute of fresh water, find their urgent thirst allayed by soaking their 

 clothes in salt water, and wearing them in that state; but these effects 

 are in part due to the hindrance to the evaporation of water from the 

 skin. 



Through the Lungs. It is a remarkable fact that not only is the 

 epithelium of the pulmonary air vesicles able to allow the passage 

 through it of gases and volatile substances, but that also under certain 

 conditions fluids such as water may also be absorbed, and besides this, 

 the presence of carbon particles in the bronchial glands and elsewhere 

 in connection with the lungs must point to the pulmonary epithelium 

 as the only possible channel of their absorption. 



