xiv THE LYMPH 537 



Fig. 255 gives au idea of the mode in which these multiple 

 elements are connected and intermingled in the areolar tissue of 

 human bone marrow. 



From what has been said, the great functional importance 

 of bone marrow will readily be admitted. The red marrow, like 

 all other lymphoid tissues, certainly contributes to lyinphapoiesis, 

 owing to its content of leucocytes at various stages of development. 

 Since the different varieties of leucocytes differ in chemical 

 constitution inasmuch as they show granulations that stain 

 differently with special pigments it is not improbable (as sug- 

 gested by Trambusti) that their specific metabolism may serve for 

 special functions, of which, however, we are at present entirely 

 ignorant. 



.It is more interesting to consider the functions of the mega- 



m 



FJU. 25ti. Megacaryocyte of bone marrow, with resting nucleus and finely granular cytoplasm, 

 differentiated into three layers, and containing five leucocytes in process of digestion. 

 (Trambusti.) 



caryocytes, on which much work has been done. The cytoplasm of 

 some of these (particularly in the first stages of acute infections 

 experimentally produced in animals) often contains corpuscles, 

 which in their characteristics in no way differ from common 

 leucocytes (Fig. 256). They were at first regarded as leucocytes 

 in process of formation by endogenous mitosis, or gemmation of 

 the nucleus of giant cells. Later researches have shown, however, 

 that they are worn-out leucocytes in process of degeneration, 

 which are actively absorbed by the giant cells, and are destined to 

 be digested by them. It is possible under the microscope to 

 follow the different phases of digestive necrosis of the ingested 

 leucocytes, by means of double staining with safranin and indulin 

 (Trambusti). These observations exclude the suggestion of 

 Heidenhain, that in cases in which leucocytes are included in 

 giant cells the former are the active invaders, and the latter the 



