LAMBLIA INTESTINALIS 



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the very motile tail-like appendix in the frontal plane is flattened. 

 The excavation at the anterior extremity, which is directed obliquely 

 forward and with its border projecting backwards and interrupted, 

 no doubt corresponds to the peristoma and serves as a clinging 

 organ. The first pair of flagella (anterior flagella) arise from its 

 anterior edge, the second and third pairs (lateral and median 

 flagella) from the posterior edge, whereas the tail flagella are 

 inserted at the posterior end of the tail. In life the anterior 

 and lateral flagella sway only with the thinner part projecting 

 beyond the body ; in the rest of their course they appear to be 

 almost attached to the body ; the median and tail flagella are quite 

 free. There are knob-like formations at their origin. The entire 

 flagellate apparatus appears to be connected with the nucleus. 



FIG. ii. Lamblia intestinalis, from the surface, from the side, on intestinal epithe- 

 lium ceils, dead and encysted. (After Grassi and Schewiakoff. ) 



The nucleus is of a dumb-bell shape, has a nucleolus in each half, 

 and lies anteriorly in that part of the body that is excavated. 

 Division forms have not been observed, but there are encysted 

 stages. The oval cysts (fig. n) measure o-oi mm. in length 

 by 0-007 mm - in breadth, they are surrounded by a fairly thick 

 hyaline layer, through which the contour of the creature can some- 

 times be seen quite distinctly. 



Lamblia intestinalis inhabits the anterior part of the small intestine of 

 various mammals (species of Mus and Arvicola, rabbit, domestic dog and cat, 

 sheep) and of man. Encysted forms are found in the colon and in the 

 faeces. If there is increased intestinal peristaltic movement the free forms 

 also appear in the evacuations, in which, however, they perish if kept long* 

 especially if the temperature is lowered to o C. or raised above 40 C. 

 Although they frequently appear in large numbers they cause no dis- 

 order ; at all events, hitherto no stringent reasons have been brought for- 

 ward to cause the Lamblia to be considered pathogenetic. On the other 



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