56 THE ANIMAL PARASITES OF MAN 



the onset of intestinal complaints, or at least of adding to them. They 

 have been found in cases of carcinoma of the stomach, and in other 

 diseases of that organ in which the acid reaction ceased. 



Naturally, whether all the reports relate to the same species of Trichomonas 

 must remain undecided. Certain authors (Steinberg, Cohnheim, van Emden) 

 accept several species. Provvazek speaks of a variety of T. intestinalis inhabiting 

 the oral cavity. This was distinguished by a posterior process exceeding the 

 length of the body fourfold, and by a somewhat unusual course of the undulating 

 membrane. The food of this form, which was found in the whitish deposit present, 

 especially in the cavities of carious teeth, consisted almost exclusively of .micrococci. 

 Schmidt and St. Artault named the Trichomonads found in pathological products 

 (e.g., gangrene, putrid bronchitis, phthisis) of the lungs of man, as Trichomonas 

 pulmonalis. Trichomonads have also been found by \Vieting in lobular pneumonia 

 in the lungs of pigs. 



It is still uncertain in what way the infection takes place. Experiments in the 

 transmission of free trichomonads to mammals (per os), in which the same or allied 

 species occur (guinea-pigs, rats, apes), have been without result. Probably encyst- 

 ment is necessary. Such conditions are mentioned by May, Kiinstler, Roos, 

 Schurmayer, van Emden, Prowazek, Galli-Valerio and Schaudinn. According to 

 Prowazek, intestinal trichomonads of rats become encysted for conjugation. In the 

 cyst an accumulation of reserve food material occurs, causing distension. The nuclei 

 of the conjugants each give off a reduction body and, after fusion, produce the 

 nuclei for the daughter individuals. According to Schaudinn the intestinal tricho- 

 monads lose their flagella before conjugation, become amoeboid and encyst in twos, 

 the formation of a large agglomeration of reserve substance accompanying this. 

 Galli-Valerio found double-contoured cysts in the fasces of trichomonad-infected 

 guinea-pigs, after the faeces had been kept for a month in a damp chamber. When 

 exposed to heat small flagellates escaped from them. Administration of such material 

 containing cysts resulted in severe infection with trichomonads, and death of the 

 experimental guinea-pigs followed. The cyst wall is clearly a protection against the 

 deleterious acid reaction of the stomach contents. Alexeieff(i9i i) and Brumpt (1912) 

 think that the trichomonad cysts of man are really fungi, while other workers also 

 doubt encystment among trichomonads. Wenyon (1907) states that T. intestinalis in 

 mice produces spherical contracted forms which escape from the body in the faeces. 



Air, water, and under certain circumstances even food may be regarded as 

 vectors for the trichomonads. The occurrence of the organisms in the oral cavity, 

 and still more so in the lungs, is in favour of the air being the transmitting agent. 

 An observation made by Epstein supports the idea of water transmission. Multipli- 

 cation of the trichomonads, once they have gained access to the body, is effected by 

 longitudinal division commencing at the anterior end (Kiinstler). " Cercomonads " 

 with several flagella and an undulating membrane, as well as trichomonads, have 

 been observed by Ross in some cases of cutaneous ulcers. 



Mello-Leitao (I9I3) 1 has described flagellate dysentery in children 

 in Rio de Janeiro. He states that it is due to T. intestinalis 

 and Lamblia intestinalis either separately or together. Flagellate 

 dysentery, he thinks, is benign and is the most frequent form of 

 dysentery in infants. The flagellates are pathogenic to infants under 

 three years of age. Escomel (iQis) 2 found 152 cases of dysentery in 

 Peru due solely to Trichomonas. Such cases are probably widespread 



1 Brit. Journ. Children's Diseases, x, p. 60. 2 Bull. Soc. Path. Exot., vi, p. 120. 



