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Notes on Toxoplasma gondii. 

 By Helex L. M. Pixell, B.Sc, Beit Memorial Beseareh Fellow. 



(Communicated by Prof. E. A. Minchin, F.E.S. Eeceived April 12. — 

 Bead May 29, 1913.) 



[Plate 9.] 



The genus Toxoplasma.' was founded by Xicolle and Manceaux (3, 4, 5) for 

 T. gondii, a species discovered by them parasitic in the gondi (Ctenodactylus 

 gondii) in Tunisia. When first discovered the parasite was identified as a 

 new species of Zeislanania. Further investigation showed, however, that its 

 resemblance to the true Zeishmania type was quite superficial, since it 

 neither possessed a kinetonucleus nor gave rise to flagellated forms in 

 cultures, consequently it was made the type of the new genus Toxoplasma. 

 of which the affinities and systematic position are at present very doubtful. 

 Since then other species of Toxoplasma have been described from rabbits in 

 Brazil (T. cuaiculi, Carini), from dogs in Italy and Brazil (T. canis, Mello), 

 from moles in Japan (T. talpce, Prowazek). and from pigeons in Brazil 

 (T. columbce, Yakimoff and Kohl-Takimoff'[10] ). 



Very recently Xieolle and Conor (6) have given an account of the parasitism 

 of T. gondii and the reactions of susceptible experimental hosts. 



In January of this year Dr. Xicolle most courteously presented 

 Prof. Minchin with some mice, two of which had been inoculated from an 

 infected pigeon at Tunis. These were brought to the Lister Institute and 

 handed over to me for study. I am indebted to Prof. Minchin not only 

 for the privilege of examining so interesting a parasite but also for much 

 kind help and advice. 



The two infected mice died shortly after their arrival in England : one, in 

 fact, on the night after it arrived in London. In order to preserve the strain 

 of the parasites, other mice or pigeons were inoculated by Prof. Minchin 

 from those that died. I have thus been able to make post-mortem examina- 

 tions of animals that had died recently from the effects of the parasite or had 

 been freshly killed. 



Although I propose in this memoir to deal chiefly with the minute 

 structure and reproduction of Toxoplasma, which has never yet been studied 

 by cytological methods, I may also refer briefly to some points in the 

 occurrence of the parasites and their effects on the experimental hosts that 

 have come under my observation in the course of the work. 



