ON A NEW RHIZOPOD PARASITE OF MAN. 



93 



conditioned Amœba and the cells in question definitely establishes the derivation 

 of the latter from the former. In fig. 4 is represented a specimen which is 

 evidently on the verge of becoming morbid. It still shows signs of life inasmuch 

 as it possesses some pseudopodia, but the knob is stretched out to a great extent by 

 the vacuoles that are encroaching upon it Indication is not wanting that a part 

 of the swelling contents has protruded itself hernia-like through the opening of 

 the enveloping membrane. Should the pseudopodia in such a specimen cease to 

 exist with the extinction of life and the body swell somewhat more as the result 

 of imbibition, the metamorphosis into the state of the above described cells would 

 be completed. 



As already mentioned, both the living and the dead individuals were found 

 together even in the freshest fluid, still warm and guarded against injurious in- 

 fluences. Care was taken to sterilize all the wares and instruments that were to 

 come into contact with the fluid and observations were made by means of a 

 microscope to which was fixed an arrangement that effectually kept the prepara- 

 tion at the normal body-temperature. Examined under such precautions, every 

 preparation made of a drop of the fluid always contained the Amoeba in the two 

 conditions referred to, in such a number that it hardly ever needed a much pro- 

 longed search to come across one or the other kind, even though the power used 

 were a moderately strong one. Preparations of the sediment, that formed itself 

 after standing for some time, of course contained the parasites in much larger 

 proportions, the majority of which were dead and adhering together in clusters. 

 In the fluid kept overnight, they were almost all, if not without exception, dead 

 and much swollen up. It is important to mention that it made no difference on 

 their mortality whether the fluid was allowed to cool or kept in a warm chamber 

 at the body-temperature ever since its extraction. Let it be also mentioned here 

 that I have not been able to observe the mode of reproduction, beyond what is 

 suggested by the possession of more than one nuclei or the occasional occurrence 

 of biscuit-like forms (fig. 5, b). 



The above observation tends to show, in my opinion, that the serous fluid was 

 not a medium fit for the parasite to continue its vigorous existence, — that the real 

 place of its parasitism is to be sought somewhere else than in the fluid that 

 contained it. The parasites were evidently dying ofl' in the serous fluid while 



