MODE AND RESULTS OF INFECTION. 189 



Unfortunately nothing is known of the life-history of Amceba coli. 

 We do not even know its mode of reproduction. But the very 

 abundant occurrence of the parasite leaves no doubt that reproduction, 

 and that a most prolific one, does take place within the intestine. 

 For in the hospital, where a continued supply of the parasite from an 

 external source was hardly possible, no diminution was perceptible, 

 though the daily voiding went on for four months. The most natural 

 supposition is, of course, that the reproduction took place by division, 1 

 as has been directly observed in other Amcebce ; see especially F. E. 

 Schultze's observations on Amoeba polypodia. 2 



As regards the mode of transmission, we are of course left to 

 hypotheses, which are all numerous as they may be without ex- 

 ception destitute of foundation, since we do not know whether the 

 Amceba coli lives exclusively in the intestine, or is parasitic only 

 accidentally. There are, indeed, some free- living species which closely 

 approach this form in their appearance and mode of motion. Losch 

 has, in this connection, drawn attention to . Amceba princeps, Auerb., 

 but it seems to me to resemble still more closely A. Maginia, lately 

 described by v. Mereschowsky. 3 This suggestion receives some proba- 

 bility from the fact that this form is found " in great abundance in 

 the sand and mud at the bottom " of the Jelaginic ponds near St. 

 Petersburg, in the same locality, that is, in which the above-men- 

 tioned patient had presumably become infected with his parasites. 



The patient had lived a most miserable life, sleeping in half-built 

 barracks, protected neither from wind nor rain, and was mainly occu- 

 pied in dragging logs out of the water. It is, therefore, likely that he 



1 [In view of the above-mentioned formation of spores in Amoeba, one can hardly help 

 believing that this process plays an important part in the reproduction of parasitic forms, 

 and this so much the less, since Grassi has published his investigations upon a species 

 (Amceba pigmentif era) parasitic on Sagitta (Rendiconto Instit. Lomb., vol. xiv., 1881) ; and 

 since Brass ("Die thierischen Parasiten des Menschen," Cassel, 1884) and others have 

 observed the same process in the intestinal A mcebce of the mouse and frog. 



Cunningham also observed an encapsulation in the case of his Protomyxomyces, when 

 cultivated in the free state (in alkaline cows' dung). But within these cysts were developed, 

 not swarm-spores, but resting-spores, with a cuticular envelope, which either remained in 

 groups or separated from each other. From these spores Cunningham believes, though he 

 has not actually observed it, that the ciliated intestinal parasites arise, which in their 

 turn, after manifold variations, give rise to resting-spores again. R. L.J 



2 Archiv f. mikrosL Anat., Bd. xi., p. 592, 1875. 



* Archiv f. mikrosL Anat., Bd. xvi., p. 204, Taf. xi., Figs. 29 and 30, 1878. The 

 description accompanying the figures runs as follows: "The form of the body varies 

 exceedingly. The body sends out short round processes, but the movements are not due 

 to these, but to the Amceba flowing en masse. The contents consist of coarse and fine 

 granules, both kinds being present in abundance. The ectoplasm is distinctly separated 

 from the endoplasm. Besides the nucleus there are also some vacuoles visible, which con- 

 tract very rapidly in the interior of the body. The consistence is fluid, the movement 

 rapid. The diameter varies from 0'02 to 0'04 mm." 



