60 THU ANIMAL PARASITES OF MAN 



The parasite under discussion was first observed by Lambl (1859) in the mucous 

 evacuations of children. He regarded the parasite as a Cercomonad and termed 

 it Cercomonas intestinalis, which name as a rule is applied to Cercomonas hominis, 

 Davaine, although Stein had already pointed out the difference between the two species, 

 Grassi (1879) observed this species first in mice (calling it Dimorphus muris), and 

 subsequently in human beings in Upper Italy and named it Megastoma entericum. 

 Biitschli and Blanchard then laid stress on the identity of this species with Lambl's 

 C. intestinalis (1859), and consequently called it Megastoma intestinal e. Later, 

 Blanchard drew attention to the circumstance that the generic name Megastoma 

 chosen by Grassi had already been used four times for various kinds of animals, 

 and established the genus Lamblia. Accordingly, L. intestinalis is the valid name,, 

 and should be generally adopted. 



In Upper Italy the parasite in the encysted condition has also been seen by 

 Perroncito in man. At the same time, Grassi and SchewiakofF began a new 

 investigation of specimens from mice and rats. In Germany, L. intestinalis 

 was found by Moritz and Holzl, Roos, Schuberg and Salomon. Moritz and Holzl 

 confirmed the relative frequency of the species. In Konigsberg, Prussia, a student 

 found encvsted Lamblia in his faeces. One case was reported from Finland by 

 Sievers, another case from Scandinavia by Miiller. Frshezjesski and Ucke reported 

 cases from Russia. Jaksch announced the occurrence of the parasite in Austria ; 

 Piccardi mentioned their presence again in Italy. They were reported from Egypt 

 by Kruse and Pasquale, and from North America (Baltimore) by Stiles. Noc stated 

 that 50 per cent, of the population of Tonkin harboured Lamblia. Finally, the 

 structure of L. intestinalis has been described by Metzner (1901), and by Wenyon 1 

 (1907) in mice. 



In all these cases L. intestinalis has been observed in the small 

 intestine, or in the evacuations of patients with intestinal diseases, 

 It has also been found in the intestine of healthy subjects. Just as 

 Trichomonas intestinalis may be found inhabiting the stomach in 

 diseases of that organ, in which an alkaline reaction is present 

 (carcinoma), so has L. intestinalis been found to occur under 

 similar circumstances (Cohnheim, Zabel). However, in Schmidt's 

 case, i per cent, hydrochloric acid was certainly stated to be present. 

 Infection takes place by the ingestion of cysts (fig. 20, e), as was 

 established by Grassi, experimentally on himself. Cereal food-stuff s, 

 contaminated with Lamblia cysts from vermin of the locality, such as 

 rats and mice, serve to convey the infection to man. Such cysts may 

 probably be found in street-dust, etc. Stiles induced infection in 

 guinea-pigs, and Perroncito in mice and rabbits, by means of cysts 

 of Lamblia from human beings. Stiles suspected that flies could 

 transport Lamblia cysts. Mathis (1914) found that L. intestinalis 

 was not amenable to emetine, at any rate in its cystic stage. 



Order. Protomonadina, Blochmann. 



The smallness of the Protomonadines and their less superficial 

 situation than the Polymastigines, may be the cause that so far as 

 the species occurring in man are concerned, they were formerly less 

 well known. As regards parasitic species, this group may be divided 



1 Arch. f. Protistenkunde, Suppl. i, p. 169. 



