PATHOLOGICAL SIGNIFICANCE. 245 



nesses of his observation, thought he could distinguish a ventral and 

 dorsal surface in the parasites which he kept alive for a week in their 

 usual liquid. The latter surface has, he says, a firmer parenchyma 

 and smoother contour, while the ventral is softer and more mobile. 

 This appearance of greater mobility arises partly from the play of an 

 opening situated at the base of the flagellum, which obviously repre- 

 sents a mouth, and is surrounded by contractile borders. Besides 

 some strongly refractive granules, two pulsating vacuoles could be 

 distinguished in the hyaline parenchyma posteriorly. 1 A division 

 was also observed, both in the mobile forms and in those which had 

 contracted into a ball, and had lost apparently both flagellum and 

 tail. Finally, the twin forms are connected together only by a thin 

 thread, which has been regarded as the flagellum. 



Even if the reproduction of Cercomonas had not been directly ob- 

 served, yet the consideration of its occurrence in immeasurable num- 

 bers would have necessarily led us to the same result. The possibility 

 of an oft-repeated and sustained importation, which one could perhaps 

 admit when the parasites inhabit the intestine, is here excluded by the 

 facts of the case. Not only because the patient, a gardener, spent the 

 last two months of his life in the hospital, in which such an importa- 

 tion could hardly take place, but, still more cogently, because on post 

 mortem examination the parasites were found exclusively confined 

 to the Echinococcus-s&c, not a trace of them being found in the 

 intestine. We must of course suppose that the Cercomonas had pene- 

 trated into the liver from the intestine, but that had probably taken 

 place a long time before, perhaps at the commencement of the Echino- 

 cocc-^s-disease, which had lasted for five years, according to the patient's 

 report. Perhaps at that time the patient harboured the Cercomonas 

 throughout the whole intestine, and the hepatic parasites, becoming 

 continually more perfectly encapsuled by the JEchinococcus-cyst, are to 

 be regarded as the last survivors of a previous intestinal disease. 



Be this as it may, this much is certain, that the case here cited is 

 not merely the only one of the kind, but has also a special interest in 

 connection with the history of Cercomonas. 



The cases observed by Ekeckrantz, Tham, and Zunker of Cerco- 

 monas in the intestine occurred in individuals who had all suffered 



1 According to Zunker's description, Cercomonas intestinalis has "a longish, oval 

 body, pointed behind, of O'Ol to 0'013 mm. in length ; at the posterior end is a strong 

 spine, and at the anterior a long flagellum, not measurable on account of its constant 

 motion. It has also granules lying in a transparent body, and generally a single vesicular 

 nucleus." A second form, only twice seen by Zunker, along with other intestinal Monads, 

 is compared to the Nonas lens, Ehrbg. It had only a third the dimensions of the 

 common Cercomonas, and a round body, which showed no differentiation, and was in 

 constant motion. 



