Xotes on Toxoplasma gondii. 



69 



Major S. E. Christophers tells me that the serous membranes hare not, so 

 far as he is aware, been examined in cases of Kala Azar, and he suggests 

 that the systemic parasite, Leishmania donovani, may possibly be found to 

 infect the membranes and peritoneal fluid in patients suffering from this 

 disease also, since the two parasites seem to be similar in so many other ways. 



In preparations of the stretched omentum, stained with silver nitrate and 

 the other reagents mentioned below, large pavement cells may be seen 

 crowded with as many as sixty or seventy parasites (fig. 6), other cells may 

 have only one or a few toxoplasms (fig. 5). In the latter case the nucleus 

 of the host-cell sometimes retains its normal oval contour with one or two 

 distinct nucleoli (fig. 5, a), but in all those enclosing more than two or three 

 parasites the nucleus has become more or less rounded, with the chromatin in 

 several blotches, giving a decidedly necrotic appearance. In fig. 5 it will be 

 seen that the central cell (a) is uninfected and normal ; the right-hand one (b) 

 contains two parasites and already the nucleolus is beginning to break up. 

 In the left-hand cell (c) the degeneration of the nucleus has advanced farther 

 still, though not so far as the nuclei of the cells represented in figs. 4 and 6. 

 In these, as in many other cases, two such necrotic nuclei are present, which 

 fact seems to suggest that after nuclear division had taken place, the infected 

 cell had not sufficient vitality for the division of the cytoplasm. 



The long, narrow, endothelial cells, which in many cases show branching- 

 ends, are also very often full of parasites, and although the nucleus in these 

 may remain more or less oval, it could not be mistaken for that of a normal 

 cell, owing to its general necrotic appearance. In transverse sections of the 

 mesenteries parasites could be distinguished not only in the flat endothelial 

 pavement cells forming the serous membrane, but also in the connective 

 tissue corpuscles of the subserous areolar tissue. Xone, however, was 

 observed free in the lymphatics or capillary blood-vessels, nor in their 

 endothelial linings. 



In mice, such as B, I, and J, described below, which were found with only 

 very few parasites in the peritoneal fluid, the mesenteries also seemed to be 

 destitute of them, and in such cases very few toxoplasms could be found 

 anywhere in the body. 



(3) Liver. — The parasites here are less numerous than in the peritoneal 

 fluid. When p resent they are frequently seen to be dividing, and may be 

 free (figs. 13-15), or in the monomiclear leucocytes, never apparently in 

 hepatic cells. In Mouse L, in which the infection lasted 15 days, the liver 

 had become pale and friable, and was much hypertrophied. 



(4) Spleen. — This organ generally has fewer parasites than the liver. They 

 may be included in mononuclears or be free. 



