210 SUMMARY OF THE ACTION OF THE LIVER. 



piration, permit this substance to reach the aortic circulation, from which 

 it is removed by the kidneys, a diabetes arising. So far as the prepara- 

 tion and course of this sugar is concerned, the liver is a ductless gland, 

 and, with Mr. Handfield Jones, I believe that the cells of the liver are the 

 agents which accomplish this duty. The production of fat appears to be 

 inversely as that of sugar. In the crustacean bile-sac, Fig. 82, we see 

 the gradual stages of its appearance ; and the production of both bodies 

 .is well illustrated in the life of plants. 



Second. The bile is separated from the blood portion of the portal 

 blood, and not from the products of digestion obtained from the chylo- 

 poietic viscera. The elements of bile I believe to pre-exist in the blood, 

 and to escape from the portal veinlets to the biliary ducts by mere filtra- 

 tion or strainage. The precise source from which the bile is derived 

 is probably the blood- cells, and in the changes which they are under- 

 going the spleen is perhaps concerned. If this be so, the bile-duct is 

 as much a duct for the spleen as it is for the liver itself. The bile may 

 almost be looked upon as a hydrocarbon, containing a very changeable 

 and therefore noxious coloring material, which, when the secretion reach- 

 es the intestine, is parted from it and dismissed with the fteces, the prop- 

 er hydrocarbon being taken up by the absorbing arrangement for hydro- 

 carbons, the lacteals, and so sent through the thoracic duct. Perhaps, 

 also, by reason of its special adaptedness for that purpose, it aids in the 

 absorption of other fats. 



At this point it may be remarked that the view here presented of the 

 sugar-forming and bile-straining functions of the liver appears to be 

 greatly strengthened by the anatomical construction of that organ. 

 There is no obvious communication between the portal and hepatic vein- 

 lets save through cells, but the portal veins and the bile-ducts run in 

 their ramifications side by side. 



Third. Whatever part of the disintegration of old blood-cells takes 

 place in the spleen, their final destruction is doubtless accomplished in 

 the liver, this being the immediate source from which the bile itself is 

 derived. Though these metamorphoses are, to a greater or less extent, 

 occurring throughout the circulation, it is in these two great glands that 

 an opportunity is afforded for the destruction to reach it's completion, and 

 the resulting product of waste to be removed ; nor is there any thing in 

 this view at all contradictory to the opinion I have enforced, that all the 

 constituents of the bile may be found in the general circulation. 



Fourth. The liver also aids in the preparation or maturation of young 

 blood-cells in an indirect way. There are certain of the mineral constit- 

 uents of the disintegrated cells too valuable to be cast away, since they 

 can subserve the duty of entering into the composition of young cells 

 passing toward perfection. As such a substance may be mentioned iron. 



