Further, by direct injection of peptone into a lymphatic vessel, Shore has shown that even so small an amount as 0.049 gramme is not assimilated or transformed by the lymph in half an hour. Consequently, we seem to have strong evidence that peptones are not prone to direct alteration of any kind by the leucocytes of the lymphatic system. Further, it would appear that the lymphoid cells of the spleen are equally unable to assimilate small amounts of peptone injected into the splenic artery. Leucocytes, then, can play no direct part in the absorption of the products of proteolysis from the intestine; the lymph is normally free from both proteoses and peptones, and the leucocytes plainly have no power to transform these bodies into other forms. They can only utilize the proteid material elaborated from the products of proteolysis by other agencies. Plainly, proteoses and peptones in the blood and lymph are foreign substances. When present in the circulation they give rise, as we have seen, to an increased flow of lymph and to a change in the coagulability of the blood. Further, not only is the flow of lymph augmented but there is likewise an increase in the amount of solid matter, while a corresponding decrease is noticed in the solid matter of the blood-plasma. This fact obviously gives support to the view that the increased formation of lymph after the injection of peptone is due to an active process of secretion by the endothelium cells of the capillary walls.[230] Further, as we have seen, peptone disappears from the blood more or less rapidly after its injection, so that it is quite possible that the loss or alteration of the coagulability of the blood may not be due to the peptone itself, but rather to an altered condition of the blood induced by the peptone. Moreover, this altered condition of the blood may be the real cause of the increased transudation, or secretion of lymph so conspicuous after the injection of peptone. Starling, however, by carefully conducted experiments on dogs finds, in conformity with Heidenhain’s views, that peptone injected into the blood exercises a direct excitatory effect on the endothelial cells, causing thereby an increased flow of lymph; the increased flow being in no way caused by the change in the blood that is simultaneously produced. Further, it would appear, according to Starling’s views, that the change in the coagulability of the blood is not due to the effect of the peptone on the endothelial cells of the blood-vessels, or at least on their lymph-producing functions. Thus, the injection of peptone may result in an action on the endothelial cells of the blood-vessels, thereby increasing the flow of lymph, or on the blood itself with a destruction or diminution of the clotting power of the blood; the two results being more or less independent. Further, the rapid transferences of peptone from the blood to the lymph is effected by the selective activity of the endothelial cells