LOESCHIA 



Bionomics. — L. coli lives in the lumen of the intestine, and feeds 

 upon the contents of the bowel. 



Diagnosis. — ^Amoebae moving slowly with pale non-refractile 

 pseudopodia, with a thin rim of ectoplasm and with an endoplasm 

 containing all sorts of organisms and no red cells, and with a large 

 distinct nucleus, are L. coli, and this diagnosis should be confirmed 

 by the discovery of the cyst because — ■ 



1. The typical characters are liable to considerable changes, 

 and the amoeba may be very like L. histolytica, as will be 

 emphasized below. 



2. Wenyon and O'Connor's researches confirm that L. coli 

 will not, as a rule at all events, ingest red blood-corpuscles. 



With regard to the cysts, they measure from 13-38 microns, but 

 the average is over 25 microns; the typical cyst has eight nuclei 

 and the very large cysts sixteen. At times chromidial bodies may 

 be present, making them look like L. histolytica cysts, from which 

 they are to be distinguished by the number of nuclei, which in the 

 motions is generally eight. 



Fig. 50. — Loeschia coli Schaudinn, Vegetative Form, stained. 

 ( X 1950 Diameters.) 

 (After James.) 



Carriage by House-Flies.— Wenyon and O'Connor, working in 

 Egypt, have shown that L. coli and L. histolytica cysts can be in- 

 gested by house-flies (Musca, Fannia, Calliphora, and Lucilia) which 

 have fed on faeces containing such cysts. These cysts can live in 

 the gut of the fly so long as any faecal matter remains there, but 

 die after all the faecal matter has been expelled, which takes place 

 some twenty-four hours after the faecal feed. The cysts may be 

 seen in the droppings of the fly as early as five minutes and as late 

 as twenty-four hours after the faecal feed. 



As to the conveyance of cysts on the exterior of the fly, the 

 observations of Kuenen and Swellengrebel and Nicol show that 

 flies do not move far until they have cleaned themselves, so that 

 but little faecal matter is left, and as this dries the cysts perish. 



Method of Infection. — ^The experiments of Calandruccio and of 

 Wenyon and O'Connor have proved that infection takes place 

 per OS, and is due to the cysts; and that, further, these are intro- 

 duced most probably by food contaminated by the cj/st-laden 

 faecal matter of house-flies. 



Pistribution. — L. coli is found in both the tropics and the Tem- 



