GENERAL RELATIONS OF EXCRETING PROCESSE3. 423 



of supporting the powers of the body by judiciously-devised means, and 

 of aiding the elimination of the morbid matter through tlie lungs and 

 skin by a copious supply of pure air, than of interfering more actively 

 to promote that which Nature is already effecting in the raost advanta- 

 geous manner. 



753. In like manner, the Liver is charged with the separation of 

 hydrocarbon, in a fluid form; for which a supply of oxygen is not 

 requisite. This product is partly derived from the waste of the sys- 

 tem ; but the arrangement of the biliary vessels leads to the belief, that 

 part of it may be at once derived from crude matter, taken up by the 

 mesenteric veins, and eliminated from them by the hepatic cells, with- 

 out ever passing into the general circulation. And various facts seem 

 to indicate, that the Liver is also destined to remove from the blood 

 extraneous substances, which are noxious to it. Thus, in cases where 

 death has resulted from the prolonged introduction of the salts of Cop- 

 per into the system, a considerable amount of that metal has been ob- 

 tained from the substance of the gland. 



754. It has been already pointed out ( 726), that in those tribes of 

 animals whose respiration is feeble, a considerable part of the mass of 

 the liver is composed of fatty matter ; and this condition may be in- 

 duced, as a state of disease, in warm-blooded, energetically-respiring 

 Birds and Mammals, by impediments to the due performance of the 

 respiratory process. This is remarkably shown in the treatment of the 

 geese which are to furnish the celebrated Strasburg pates. The unfor- 

 tunate bird is closely confined at a high temperature ; 



so that the respiration is reduced to its minimum amount, Fi g- 131. 

 by the combined effects of warmth and muscular inac- 

 tion ; and it is then crammed with maize, which contains 

 a large amount of oily matter. The consequence is, that 

 its liver soon enlarges, and becomes unusually fatty ; its 

 cells being gorged with oil-globules, instead of each con- 

 taining no more than one or two : and it is then ready 

 for the epicureans who set so high a value on the pate 

 de foie gras. A similar diseased condition of the liver 

 frequently presents itself in Man, in connexion with chronic dis- 

 orders of the respiratory organs, which diminish the amount of hydro- 

 carbon eliminated through their agency ; this "fatty liver" is peculiarly 

 common in the advanced stages of Phthisis. Jt may arise, however, 

 from a local disorder of nutrition, such as that which produces the 

 fatty degeneration of other organs. Such a fatty degeneration may 

 occur in the Kidney, for example, as a consequence of inflammation of 

 its tissues. 



755. With regard to the Kidneys, it has been already pointed out 

 that they are the special emunctories of the azotized products of the 

 decomposition of the tissues ; and that they serve also to convey away 

 the overplus of such earthy and alkaline salts, as are readily soluble. 

 Moreover, it has been shown that the surplus proteine-compounds, 

 which are not required for the nutrition of the system, must be 

 excreted by their agency, after having been metamorphosed into urea. 

 And we have now to notice, that other matters of an injurious charac- 



