764 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



tracing tlie fact of its appearance in these countries to certain habits 

 of living which facilitate the transference of the parasite from the pig 

 to man. In his description of the structure of this Infusorian, he 

 gives an improved account of the peristome, mouth, oesophagus, and 

 nucleus, but could not find the nucleolus mentioned by Wising. The 

 conjugation observed by Wising is detailed, and a corrected account is 

 given of the process of fission, which goes on as described by Stein of 

 B. entozoon. The transmission of the parasite takes place in the 

 encysted state, as may be inferred with probability from analogy 

 with the parasitic OpalinaB as well as by direct observation, at any 

 rate of the specimens found in the pig ; hence the process of infection 

 of man by the pig may be readily concluded. The pathological im- 

 portance of Balantidium may probably be set down as similar to that 

 already shown to hold in the case of the Amcebae and Monads of the 

 intestine. 



Parasitic Protozoa, especially those of Man.* — The following 

 notice relates to the parasitic Protozoa observed by Grassi during 

 a not very lengthy period of investigation (July to October, 1879). 

 The chief locality was Eovellasea in Lombardy. The Ehizopoda 

 were represented by a Moneron of doubtful character which was found 

 in blood (of what animal not stated), extremely seldom, and by a 

 number of AmxBbce,. Among the latter, that interesting and not unim- 

 portant inhabitant of the human intestine, A. coli of Losch, is said to 

 have been noticed in no less than six instances. A similar form was 

 found in the colon of the mouse, and named A. muris n. sp. Besides 

 these a species named A. dentalis Grassi n. sp. (probably identical 

 with A. huccalis Steinberg) was observed in the human mouth in three 

 cases ; it is stated to closely resemble A. coli. The Amoebce of the ' 

 frog's intestine, already repeatedly studied, were included by Grassi in 

 his investigations, and named by him A. ranarum n. sp. A new 

 Coccidium (C. Bivolta n. sp.) was met with in the colon of the cat. 

 The establishment of this new species is justified chiefly by its 

 development ; the granular contents (which, it must be observed, 

 probably belong to an encysted form) divide into two roundish spores, 

 each of which produces four semilunar Moneran germs (the sickle- 

 shaped bodies of Schneider), and a nucleus de reliquat. 



A very considerable series of Flagellata are also brought forward, 

 for which the author proposes a new division into genera, considering 

 those already in use, based chiefly on the number and structure of the 

 flagella, not to be thoroughly practical, owing to the difficulty of 

 determining these characters. He proposes the name Mono-cerco- 

 monas for a genus characterized by the possession of a simple caudal 

 appendage, and divisible into four subgenera. 



Subgenus 1. Monocercomonas s. str. Naked. — M. hominis- ( = Cer- 

 comonas hominis Dav. ? G. intestinalis Lamb. ? Trichomonas intestinalis 

 (Lamb.) Leuck.). This form is described at length, and came under 

 observation in no less than 100 cases. The author endeavours to 



* Gazz. Med. Ital. Lomb., 1879, No. 45. Cf. Zool. Jahresber. Naples, I. (for 

 1879) pp. 121-3. Abstract with critical remarks by Prof. Biitschli. 



