Resorption of the formed elements 85 



The analogy between the modifications undergone by the red 

 blood corpuscles and other cells inside the macrophages and the 

 changes that take place in the intestinal cells of Planarians and 

 Actinians, suggests that the resorption of formed elements must [91] 

 undoubtedly be regarded as a true intracellular digestion. It would, 

 however, be a very important matter to be able to support this con- 

 clusion by even more convincing proofs. The study of the artificial 

 digestion that is observed in vitro in the case of the macerated mesen- 

 terial filaments of Actinians has furnished a very valuable argument in 

 favour of the enzymatic nature of intracellular digestion. Animal 

 exudations are not well adapted for this special line of study. We can 

 only obtain them as the result of the injection of different substances, 

 solid or fluid, which are greedily absorbed by phagocytes. If we collect 

 the exudations at a moment when the number of these cells is still 

 considerable we must withdraw along with them many digestive sub- 

 stances which interfere with our observation. We may therefore with 

 advantage turn our attention to masses of phagocytes collected in 

 organs. As it is mainly the macrophages which effect the resorption 

 of cells, it is evident that we must choose the centres where they are 

 formed in order to investigate the digestive ferments. Let us take, 

 then, the lymphatic glands of the mesentery, the glandular portion of 

 the omentum and the spleen, the three pre-eminently macrophagic 

 organs, and let us see if, with an extract of them, prepared with 

 physiological salt solution (075 % of sodium chloride), any digestive 

 effect is to be obtained. 



Macerate the three organs mentioned of a guinea-pig and mix 

 the extracts thus obtained with red blood corpuscles of the goose, 

 corpuscles that have already given us information in connection with 

 the phenomena of resorption in the living organism. In almost all 

 the guinea-pigs a solution of the red blood corpuscles of the goose 

 by the extract of the glandular portion of the omentum may be 

 observed. The mesenteric glands likewise give an extract which 

 in most cases has a solvent action. The extract from the spleen is 

 only active in a limited number of cases. In all these examples the 

 extracts from macrophagic organs bring about the solution of the 

 haemoglobin, but leave intact the membrane and nucleus of the 

 corpuscles. In this respect there exists, then, a certain difference 

 between this and the digestion of red corpuscles in the macrophages 

 of exudations, where the membrane and even the nucleus are in the 

 end completely dissolved. This difference may be explained by the 



