94 



vision of the myelocytes are to be seen 

 in great abundance. This hyperplasia 

 becomes marked on the 10th and 14th 

 days; the fat-cells are then hidden by 

 the parenchjina-cells. At the same time 

 there is a regeneration, on a smaller 

 scale of the cells of the htemoglobin 

 containing series. At this time, a fact 

 of general mterest is the appea- 

 rance of formations morphologically si- 

 milar to lymi)hoid follicles with a germ- 

 centre. 



It is interesting to compare the cur- 

 ve of agglutinin-production with the le- 

 sions in the bone-marrow. This curve 

 attains its maximum on the 6th 8th 

 days of immunisation (TSUKAHARA), 

 coinciding thus with a marked hyperpla- 

 sia of the cells of the myeloid series 

 and with the regeneration of the fat- 

 contents of the fat-cells of the bone- 

 marrow. 



Doubtlessly the lesions I observed 

 .are closely connected with the well- 



known modifications of fhe blood In 

 immunisation. 



I think that the action of the antigen, 

 leiicocytosis and the production of antibo- 

 dies are facts clo.sely connected among 

 themselves and that all of them concur 

 towards producing the lesions of the 

 bone-marrow seen during immunisation. 



This is not a gratuitous supposition 

 since HEKTOEN's experiments have 

 shown the «ieucocytogenic-centres» to 

 take part in the elaljoration of antibo- 

 dies and TïSCORNIA, employing a spe- 

 cial technic isolated from the leucocytes 

 of immunised animals substances with 

 immunising properties. 



Taking into account recent immu- 

 nologic research and experiments with 

 physical agents such as X-rays, radium 

 and thorium X. all of which tend to 

 point out the bone-marrow as seat of 

 production of some antibodies (aggluti- 

 nins), we may conclude that the mor- 

 phological descriptions submitted in thi« 

 work confinn this point of view. 



