A HSMOGREGARINE OF MAMMALS 107 



ut' whicli ill size and shape very closely resenilileil luemogregarine forms. (Plate XIII. ; Figs. 

 c and h.) These were seen to change into flagellated forms which were attached by their 

 short flagella to the epithelium lining tiiu gut, and kept lashing from side to side in active 

 motion. Some of them were watched undergoing longitudinal division while still attached to 

 the gut. (Plate XHI. ; Figs, c and ij.) It is worthy of note that this division began at the 

 end opposite the flagellum, and therefore presumably could not have been dependant on a 

 binary division of the luiero-nuclens, unless, ami this is interesting, these forms were 

 identical with some of the stained forms to which Fig. <■ refers. There at least one parasite 

 will be seen resembling a trypanosome in all but the absence of an undulating membrane, for, 

 as will be noted, the micro-nucleus is at the opposite end from the flagellum. 



Total length of living vemiicules . . 12 fi. 



Breadth . . . . . . . . 2 /i at broadest, i.e., anterior part. 



Length of flagella . . . . . . 3 /n. 



Amceboid forms . . . . about (i fi in either diameter. 



It was curious that at first I only found these various forms in female fleas which had 

 been fed on infected jerboas. This, together with the descriptions given by Schaudinn, 

 naturally led one to think that the third supposition was correct. Further investigations, 

 however, have served to confute this idea, for I soon began to And these appearances in 

 male fleas fed in the same manner, and finally, my assistant, Mr. Friedrichs, discovered 

 similar forms in fleas taken from freshly-caught gerbils with normal blood. It was, 

 therefore, apparent that the first supposition was the correct one, i.e., that these bodies were .^.^^^ ^^^^ 

 in reality parasites of the flea itself. That they belong to the family known as the solution 

 Crithidiii* I now have little doubt, especially after reading the interesting papers by Koss, 

 on the intestinal parasites of mosquitoes. f 



It is evident that the rosette forms are the colon ici radiees, the spherical amu'boid forms 

 are the ameehuhv, and the flagellates are the JfagelUda' which he describes, and which Leger 

 termed " formes mouadiniennes." It seems to me that these results tend to support his 

 contentions, and those of Novy and McNeal,^ against Schandinn's work, and are therefore of 

 considerable interest. Sections of fleas show clusters of the parasites, which are easily 

 recognisable. Apparently, judging from Bii't's§ list, these protozoa have not been previously 

 found in lleas. Further proof has been obtained by the discovery in one female flea of what 

 seems to be the real cycle of development of the Hamoyre^jarine, whicli proves to be precisely 

 similar to that described by Christophers for Hivinogregarina gerhdli in the louse. 



It was some time before I could obtain Christophers' paper. I then found his very 

 interesting account of the cycle passed by that parasite in Hcematopinus Stephemi.Ji This 

 is very briefly as follows : — A first stage of free verraicules is found in the mid-gut, 

 intestine, and occasionally elsewhere. This is succeeded by the formation of large cysts 

 which are found lying free in the body cavity. These large cysts contain numerous small 

 oval cysts, and these in their turn contain crescentic bodies (sausage-shaped when liberated). 

 These bodies Christophers believes to be of the nature of sporozoites. He records a 

 curious observation to the effect that contact with fresh blood plasma apparently caused 



* Leger and Dubosq. Comp. rend. Cong, de Montauban, 1902. L%er. Comp rend. Soo. de Biol., 1902. L^ger. 

 Comp. rend, del' Acad, des Sciences, 7/4/02. 



t Joum. of Hygiene, Cambridge, January and April, 1906. 



I Journ. Infect. Diseases. Chicago, March, 1905. 



§ Joum. E.A.M.C, June, 1906. 



^ Thompson Yates and Johnston Laboratories Report Vol. VIL (new series), Part I., Feb. 1906. 



