ii2 PROTOZOA AND DISEASE 



Although the tissue of this sarcoma of the testis from which the 

 sections here described were made was not quite so well fixed as 

 that of the alveolar sarcoma described above, yet the details are 

 sufficiently clear to be criticised. There is a general resemblance in 

 the optical characters, staining reactions, and nuclear divisions 

 between the bodies described as protozoa in the alveolar sarcoma 

 and those now under consideration in this round-celled tumour of 

 the testis. The sections of the latter were examined by a com- 

 mittee 1 in 1893, but they declined to express any opinion, on the 

 ground that the structure of the tissue was ' obscured by necrosis.' 

 I think they were mistaken. The areas of necrosis are quite typical 

 and easily recognised, and they have the dull appearance and loss of 

 differential staining characteristic of necrosed tissue. In their 

 striking contrast with the highly refracting areas marked by nuclear 

 figures, reticulation, etc., the necrosed areas afford a basis for 

 comparison, and actually elucidate the other areas, which must 

 either be due to some peculiar form of degeneration, or be parasites 

 passing centrally into involution-forms. They cannot be degenerated 

 tissue-cells, for their form, nuclear structure (when a nucleus is 

 present), or the total absence of a nucleus, show them to be cells 

 other than the sarcoma-cells, which, as explained on p. 109, arise from 

 the connective-tissue cells. It is unnecessary to argue the possi- 

 bility of their being leucocytes of one sort or another, because a 

 glance at the figures shows this to be out of the question. They 

 can only be parasites of the same nature as those in the alveolar 

 sarcoma. If, then, we reconstruct the life of this tumour as it must 

 have occurred about one of the small bloodvessels, the result is as 

 shown in the diagram (Fig. 44). In this scheme the contrast between 

 the tissue-cells and the foreign parasitic cells is made clear, and in 

 it I have noted my impression that where the infected tumour-cells 

 abut upon the free parasites there is no indication of the prophases 

 of mitosis, as there would be if the parasitic forms were derived from 

 the tumour-cells. Where a connective-tissue cell is found in 



1 Pathological Society of London : Report of the ' Morbid Growths' Com- 

 mittee, Brit, Med.Journ., 1893. 



