1010.] PAiiASiTTC iMunozoA or ]i\:\) tii!()i;,s!':. CiDH 



forth hy me in tAvo otliei- lueuioiis *. The i-eiii;iiuin<f Protozoa 

 found in grouse may be conveniently divided into (a) puriisites 

 of the Wood of the bird, (/a) pnrasites of the alimentary tract of 

 the grouse. Ho far I have found seven Protozoa parasitic in 

 grouse, exclusive of the ('occidmm already mentioned. 



(A) PARASIPES FOUND IN THE ]5L()0I) OF GROUSE. 



Sporozoa— Hsemosporidia. 



1. LhTCocvTO/Coox LOVATi 8eligmann ct Samlxm, lilOT. 

 (Pli.tes LIX., LX. iig.s. 1-28.) 



(a) Introductory. 



This parasite was discovered in 1907 by Seligmann and Sand)on 

 in blood-films of grouse. It was found in one bird not suflei-ing 

 from ''grouse-disease.'' Sambon (1908-9) i-efers again to the 

 para»site, and states that he found it in fi^-e mni-e gi-ouse. Snmbon 

 gives five diawings of the parasite. 



Personally, I found this pai'asite in 1909 in tliree grouse, all of 

 whicli were in splendid condition, though in one case the spleen 

 was found to l)e slightly enlarged. The parasites were in no case 

 numei'ous. and in one bird only the younger stages of the para- 

 site were seen. However, in the two i-emaining birds I had the 

 good fortune to find the parasites alive in })eripheral blood and in 

 heart-blood taken from birds freshl}' killed. Observations were 

 made on the living parasites, both unstained and after colouring 

 them intra viiavi with methylene blue (PI. LX. figs. 17-22). 

 The parasites were also seen while making blood -counts of the 

 avian hosts, when the Leiicocytozoon. stained intra vitain. with the 

 methyl-\ iolet of Toison's fluid. 



(b) TIls Relation of the Parasite to its Host Cell. 



The nature of the host-cell is controversial, some autliorities 

 considering that It is an erythi-oblast, others that it is a leucocyte, 

 while the views of son)e of the observers have changed during the 

 course of their investigations. The host-cell clearly does not 

 contain htemoglobin, and no melanin pigment is excreted by the 

 parasite. The host-cell is at fii'st round or ovoid, containing u 

 rather bi'oad and well-marked nucleus, a.nd so the host-cell must 

 be either a. mononuclear leucocyte or an erythroblast. Possibly 

 })oth these types of cells may be infected. The nature of the 

 host-cell is itihei'ently diflicult to determine in view of the fact 

 that all the blood-cells of birds aie nucleated. Judging by the 

 size of the nucleus of the host-cell (PI. LIX. figs. 1-^^), I incline to 

 the view that it is a small mononuclear leucocyte or potentially 

 such. Other workers have acknowledged the resemblance of 

 the host-cell to a mononucleai- leticocyte. However, the matter 

 can only be definitely settled by reseairhes on the origin and 



* V. Z. S. 1010, pp. H7-J-H91 ;ukI 708-72-2, 



