95 



Explanation of Figures. 



Figs. 1 to 13, Plates 18 to 22, are 

 microphotographs of microscope sections 

 of rabbit bone-marrow stained with 

 hsematoxylin-eosln. 



Figs. 14 and 15, Plate 17, are dra- 

 wings from microscopic sections of bo- 

 ne-marrow stained with hsematoxylin- 

 «osin and drawn with ZEISS' Gomp. Oc. 

 4 and Homog. Imm. Obj. 1^12; Fig. 16 

 is drawn with ZEISS' Oc. 2 and Homog. 

 Imm. 1/12. Fig. 17, Plate 17, is drawn 

 ftrom a section of bone-marrow stained 

 by GIEMSA's fluid process and exami- 

 ned with ZEISS' Gomp. Oc. 6 ZEISS 

 Obj. DD'. 



Mate 17. 



Pig. 1 — Bone-marrow at the ith 

 hoar of immunisation (rabbit 

 S69). 



Leucocytes placed round fat-cells 

 like a halo (chemolaxis of the 

 fat-cell for leucocytes). 



Pig. 2 — Bone-marrow at the ith 

 hour of immunisation (rabbit 

 369). 



Leucocytes grouped roimd fat-cell 

 are more numerous tliau in Fig. 

 14, and cover the fat-cells 



Fig. S — Bone-marrow at the end 

 of the 7th day of immunisation 

 (rabbit 218), showing an active 

 proliferation of myelocytes. 



Observe the predomination of this 

 kind of cell over the other pa- 

 renchyma-cells and its grou- 

 ping round the blood-vessels. 

 Capillaries dilated, slightly less 

 so than in the first days of im- 

 munisation. Some fat-cells are 

 approximatlvely normally-sized 

 (a): others are hidden by groups 

 of myelocytes giving at first 

 sight the impression that they 

 had been invaded by myelocytes 

 (b.) 



Fig. 4^ — Bone-marrow at the end of 



the I'fth day of immunisation 

 (rabbit 1S3-A). 



Gell-focus that must be identified 

 with a Ijinphoid follicle with 

 its germ-centre. 



The central part (germ centre) is 

 occupied by big cells of a baso- 

 phil cytoplasm, oval nucleus 

 with little chromatin and with 

 1—2 nucleoli (Feticulum-cells). 



Peripherically there are numerous 

 cells with the morphology of 

 lymphocytes, among which are 

 to be observed also cells of 

 the marrow-parenchyma (mye- 

 locytes and leucocytes). 



In these cell-foci erythroblasts are 

 not seen. 



Plate 18. 



Fig. 1 — Normal rabbit bone-marrow 

 (seen under a weak power). 



The clear spaces correspond to fat- 

 cells ; between the latter are ar- 

 ranged the parenchyma-cells. 

 Blood-vessels are not in eviden- 

 ce. 



Pig. 2 — Normal rabbit bone-marrow 

 (seen under a strong power). 



Plate 19. 



Fig. 3— Bone-marrow after 2i- hours 

 of immunisation (rabbit 212). 



Pronounced congestion and œdema 

 of reticulum (as compared with 

 with Fig. 1, Plate 18). Reduc- 

 tion in number of parenchyma- 

 cells (aplasia). Fat-cells redu- 

 ced in volume. 



Fig. 4 — Bone-marrow after 3i hour» 

 of immunisation (rabbit 212). 



(To be contrasted with Fig. 2, Plato 

 18). 



Reduction in number of parenchy- 

 ma-cells (aplasia). Abundance of 

 cells with the morphology of 

 lymphocytes. Congestion and 

 œdema of reticulum. Lesions of 

 fat-cells (cf. text). 



