286 ABSORPTION LYMPH AND CHYLE. 



uids with the food, the thoracic duct and the lacteals are very much distended 

 (Leuret and Lassaigne). In an experiment by Ernest Burdach, a dog was de- 

 prived of food and drink for twenty-four hours, after which he was allowed to 

 drink water, and in addition, half a pound(227 c. c.) was injected into the 

 stomach. The animal was killed a half-hour after, and the thoracic duct 

 was found engorged with watery lymph, which contained a very few lymph- 

 corpuscles. 



Aside from the entrance of gases into the blood from the pulmonary sur- 

 face, physiological absorption is almost entirely confined to the mucous mem- 

 brane of the alimentary canal. It is true that liquids may find their way in- 

 to the circulation through the skin, the lining membrane of the air-passages, 

 the reservoirs, ducts and parenchyma of glands, the serous and other closed 

 cavities, the areolar tissue, the conjunctiva, the muscular tissue, and, in fact, 

 all parts which are supplied with blood-vessels ; but here the absorption of 

 foreign matters is occasional or accidental and is not connected with the gen- 

 eral process of nutrition. It is now well known that all parts of the body, 

 except the epidermis and its appendages, the epithelium, and some other 

 structures which are regularly desquamated, are constantly undergoing change, 

 and the effete matters which result from their disassimilation are taken up 

 by what is called interstitial absorption, and are carried by the blood to the 

 proper organs, to be excreted. It seems probable that the vessels of these 

 parts would also be capable of absorbing soluble foreign substances ; and this 

 is, indeed, the fact with regard to all parts in which the nutritive processes 

 are even moderately active or where the structures covering the vascular 

 parts are permeable. 



Absorption by the Skin. It is universally admitted that absorption can 

 take place from the general surface, although at one time this was a question 

 much discussed by physiologists. The proofs, however, of the entrance of 

 certain medicinal preparations from the surface of the body are now entirely 

 conclusive ; and the constitutional effects of medicines administered in this 

 way are frequently as marked as when they are taken into the alimentary canal. 

 The question which is of most importance in this connection relates to the 

 normal action of the skin as an absorbing surface. Looking at this subject 

 from a purely physiological point of view, absorption from the skin, under 

 ordinary conditions, must be very slight, if, indeed, it take place at all. There 

 are, nevertheless, facts which render it certain that water may be absorbed 

 by the skin. In a series of experiments by Collard de Martigny, in 1821, it 

 was shown that water could be absorbed in small quantity by the skin of the 

 palm of the hand. In one experiment, a small bell-glass filled with water was 

 applied hermetically to the palm. This was connected with a tube bent in 

 the form of a siphon, also filled with water, the long branch of which was 

 placed in a vessel of mercury. After the apparatus had been applied for an 

 hour and three-quarters, the mercury was found sensibly elevated in the tube, 

 showing that a certain quantity of the water had disappeared. In a series of 

 observations upon the absorption of water and soluble substances, by Wille- 



