568 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Multiple fission is of three types : — 1 . Free individuals form a 

 plasmodium-like somatella of eight fully equipped zooids, in the forma- 

 tion of which the duplication of organellie keeps pace with nuclear 

 multiplication. 2. Free individuals form eight zooids, but nuclear 

 multiplication precedes the division of the organella. Encystment may 

 follow. 3. Encysted single individuals form eight-zooid, sixteen-nucleate 

 plasmodial masses with chromatic disintegration of organella, the 

 axostyles persisting longest. The small free zooids are not to be confused 

 with Hexamitus muris, which is a distinct species. No evidence was 

 found of an " Octomifus " stage of Giardia. 



There is tentative evidence of the fusion of two free individuals and 

 also of copulation cysts, which may be derived therefrom with the two 

 gametocyte individuals back to back, and of their maturation by two 

 divisions. Chromosome reduction has not been detected in these divisions. 



The most striking feature of the development of the free, sixteen- 

 nucleate, eight-zooid plasmodium, or somatella, is the preservation, in 

 each successive step of the process, of the fully equipped binucleate 

 individuals. The individuality of the potential zooids is morphologically 

 established and maintained ; and there is evidence also of their functional 

 independence in the independent motor struggles of each, which result 

 ultimately in plasmotomy. In the cases of multiple fission in cysts and 

 free individuals in whicli nuclear multiplication outruns that of the other 

 organella, this individuality is more or less disrupted, or even lost. The 

 possibility that some of these, at least, may represent involution or 

 pathological states on the part of the parasite itself, should be borne in 

 mind in all attempts to unravel the baffling significance of these protean 

 aspects of this most interesting, suggestive, minute, but by no means 

 simple organism. 



Species of Malarial Parasites.* — E. J. Marzinowsky discusses the 

 various species of Plasmodium, and establishes P. caucaskum sp. n., 

 which is characterized by peculiarities in the merozoites and annular 

 forms, and by the schizogony in the peripheral blood. He contrasts it 

 with P.prsecox, P. malar ise, P. vivax, and P. tenue (?), and points out 

 that the occurrence of different species may explain the clinical diversity 

 of cases of malaria. 



Haemoparasites of Chronic Fever, j — A. I. Fedorovitch found in the 

 peripheral blood of a fever patient from the Black Sea coast a number of 

 oval, spherical, and irregularly-shaped free parasites. Most of them had 

 one end drawn out into a thread. The nucleus was sometimes central, 

 sometimes near the thread-like extremity. It was rounded or oval, in 

 exceptional cases elongated or curved. The parasites varied from 

 2-7 fi in their greater diameter. They approached the forms (from a 

 Cinghalese with chronic fever) which Castellani has called I'oxoplasmd 

 vyrogenes, but their po&ition among Protozoa is uncertain. An analogous 

 form was found in 1905 from the blood of a dog from the Black Sea 

 coast which also suffered from fever. 



* Ann. Inst. Pasteur, xxx. (1916) pp. 243-8 (3 pis.), 

 t Ann. Inst. Pasteur, xxx. (1916) pp. 249-50 (2 pis.). 



