89 



Species LAMBLIA DUODENALIS (Davaine, 1875) Stiles, 1902, s. 1. 

 [Figs. 9 to 15.] 



SPECIFIC DIAGNOSIS. Lamblia (p. 88): Body pyriform, 5 to 16/i (21/x Lambl) long, 

 4 to 12.5/ (8.6 to lip Lambl) broad; flagella 9 to 14/x long; anterior end bluntly 

 rounded, posterior end sharply pointed, dorsum convex, antero-ventrally concave, 

 venter flat to convex; antero-ventral concavity forms a sucker, the margins of which 

 project from the surface and are contractile. Four pairs of ventral posteriorly directed 

 flagella, arranged as follows: 1 pair insert on anterior margin of sucker; 2 pairs on pos- 

 terior margin of sucker, near median line; 1 pair on posterior extremity. Body 

 membrane ("cuticula") very delicate, permitting some change of body form; pro- 

 toplasm finely granular; nucleus dumb-bell shaped, pre-equatorial. Vacuoles not 

 observed. Copulation sucker-to-sucker, followed by an encystation, in which stage 

 complicated nuclear changes occur; cysts 10 by 7/x. 



HABITAT. Upper portion of small intestine of man (Homo); also of the common 

 house mouse ( Mus musculus), the brown rat ( M. decumanus), the black rat ( M. rattus), 

 "Mas sylvestris" [=? M. decumanus], field mouse (Microtus arvalis), water mole 

 (Arvicola amphibius), rabbits, guinea pigs, domesticated cats, dogs, and sheep. 



GEOGRAPHICAL DISTRIBUTION. Europe, Egypt, and United States. 



This parasite is very common in animals in certain parts of 

 Europe, and cases of its presence in man have been reported by a 

 number of authors (Lambl, 1859; Grassi, 1881; Perroncito, 1888; 

 Moritz, 1891; Moritz & Holzl, 1892; Roos, 1893; Kruse & Pasquale, 

 1894; Piccardi, 1895; Sievers; Mueller; Frshezjesski & Ucke; Stiles, 

 1902; Braun, 1908; etc.). The indications are that it is more com- 

 mon in man than is generally assumed. 



Possibly man becomes infected through eating food (as bread, 

 etc.) which has been soiled by the excrements (containing the 

 encysted stage) of mice and rats. Grassi infected himself, Perron- 

 cito infected mice and rabbits, and Stiles infected guinea pigs by 

 feeding to them human feces containing the encysted stage. 



The parasite may be present in large numbers. Moritz estimated 

 a discharge of 18 milliards within twenty-four hours from one of 

 his patients. It has been observed in healthy persons and also in 

 cases of various diseases, but especially in children and in cases of 

 tuberculosis. It is an inhabitant chiefly of the duodenum and 

 jejunum, where it attaches itself (fig. 13) by means of the sucker to 

 the epithelial cells. It is rarer in the ileum. In case the stomach 

 is alkaline (carcinoma) the parasite may occur in this organ (Cohn- 

 heim, Zabel). In P. Schmidt's case the hydrochloric acid was 1 

 per cent. In case the intestinal peristalsis is normal the parasite 



SYNONYMS. Cercomonas intestinalis Lambl, 1859, in man (not Bodo (Cercomonas) 

 intestinalis (Ehrenberg, 1838) Diesing, 1850, in frogs; not Cercomonas intestinalis 

 (Ehrenberg, 1838) Perty, 1852); Hexamita duodenalis Davaine, 1875, in rabbits; 

 Dimorphus muris Grassi, 1879, in Mus; Megastoma enlericum Grassi, 1881 (=Dimor- 

 phus muris renamed); Megastoma intestinale (Lambl, 1859) R. Blanchard, 1885; 

 Lamblia intestinalis (Lambl, 1859) R. Blanchard, 1888; "Megastoma intestinalis" of 

 Leclerq, 1890; "Cercomonas intistinalis Lambl "of L. Pfeiffer; " Megastroma enteri- 

 cum Grassi, 1881" of Schneidemuehl, 1898; "Dimorpha muris Grassi " of Senn, 1900. 



