Notes on Toxoplasma gondii. 



75 



is, however, to all appearances a true Protozoon. Since Roche-Lima* has 

 claimed to show that Eistoplasma is a yeast-like organism, the question 

 naturally arises as to the possibility of Toxoplasma being also related to the 

 Blastomycetes. That such is not the case, however, is, I think, sufficiently 

 proved by the characteristics described above, such, for example, as : (1) the 

 constant appearance of the nucleus ; (2) the absence of a distinct refringent 

 membrane round the parasite ; (3) the fact that it does not grow in cultures ; 

 and (4) that no sign of gemmation has been observed, the parasite generally 

 dividing by longitudinal fission. Beer-wort gelatine was used for culture 

 experiments in addition to the media mentioned above, but in no case could 

 the Toxoplasma be made to grow, neither would they retain any colour when 

 preparations were stained by Gram's method. 



Nicolle and Conor (6) in their recent paper, which I saw for the first 

 time in Tunis on my way to the desert, gave some evidence of the fact that 

 Toxoplasma causes only a seasonal disease in the gondi. This I was able 

 to confirm, for during April, when I was at Matmata (the place from which 

 the disease was originally recorded by Dr. Nicolle), I could find no trace 

 of Toxoplasma, although I examined 55 gondi and numerous other indigenous 

 animals, including rats, mice, shrews, many birds, such as finches, pigeons 

 and eagles, also a palm lizard, snakes, and frogs. I also carefully examined 

 the ectoparasites of the gondi, these being in nearly every case the hexapod 

 larvte of a mite {Trombidium ?) clustered together, forming yellow masses 

 in the ears, and ticks which Prof. Nuttall and Mr. Warburton have kindly 

 identified for me as Rliipicephalus (Pterygodes) fulvus, Neumann. The latter 

 were all in the nymph stage, but some have already metamorphosed since I 

 brought them to England, and I am now hoping to make the adults feed on 

 mice, guinea-pigs, or rabbits infected with Toxoplasma. Prof. Mesnil has 

 most kindly sent me the virus for these experiments from Paris. In neither 

 of the natural ectoparasites of the gondi could I discover anything that could 

 be recognised as Toxoplasma, nor do I think that the parasite could be present 

 in an unrecognisable form, for no results have been obtained by inoculating 

 their contents into mice, gondi, and a pigeon. Dr. Nicolle most kindly 

 performed these inoculations for me, and has kept the pigeon, gondi, and 

 some of the mice under observation at the Pasteur Institute, Tunis ; owing to 

 the great delicacy of the gondi, it would not have been safe to risk bringing 

 them to London. 



I am very much indebted to Dr. Nicolle also for most kindly making 

 excellent arrangements for my visit to the desert, and for providing me with 

 * ' Centr. fur Bakter.,' 1913, Abt. 1, vol. 67, pp. 233-249. 



