IMMCJNTTY AGAINST MICROBES. 441 



large quantities of elastic fibres. The writer^ has proved that 

 iu the spleen of tuberculous animals such cells not only destroy 

 the specific tubercle bacilli, but also devour an enormous 

 number of red blood-corpuscles, these cells being found to be 

 absolutely crammed with blood-pigment (figs. I, K). 



I may here record an experiment which is extremely in- 

 teresting, as it illustrates the development and the functions 

 of giant-cells. Having inoculated a rabbit with 0*005 of first 

 vaccin of charbon symptomatique, enveloped in a paper bag, 

 I was prevented by a temporary illness from coming to the 

 laboratory. On the sixth day the animal appeared quite well ; 

 the paper bag, together with the surrounding tissue, was taken 

 out, hardened in absolute alcohol, and cut, and the sections 

 stained very deeply with carmine orM. Gerrard's logwood and 

 Grain's method. In all the sections which I examined from 

 various situations I was unable to find a single bacillus. The 

 cavity of the paper bag was still perfectly recognisable, although 

 it contained the debris of the powder used, and numerous 

 amoeboid cells. On the other hand, the outer side of the paper 

 was already permeated by young connective tissue which was 

 already vascularised. 



I need not enter here into the description of the microphages 

 (small mononucleated or multinucleated cells), or of the 

 macrophages (large cells with a single clear vesicular nucleus). 

 Suffice it to say that, contrary to the opinion of Messrs. 

 Ballance and Sherrington, who were unable to find in their 

 experiments any intermediate forms between the leucocytes 

 and the plasma-cells, I maintain that every stage of develop- 

 ment can be shown between the leucocyte and the plasma-cell. 

 The formation of the plasma-cell in pathological effusions is 

 identical with the formation of similar cells which I have 

 described in normal tissues (spleen, lymphatic glands, Peyer's 

 patch, tonsils, &c.). 2 Not only is their development the same, 

 but their functions are also identical ; for in the filter-paper 

 introduced subcutaneously, as well as in the normal spleen and 



1 Armand Ruffer, ' British MedicalJournal,' 1890. 



' "Ou Formation of Scar Tissue," ' Journal of Pliybiology,* 1889, p. 558. 



