117 



experiments, it is as concentrated a product as can be prepared 

 without conversion of thiosulphate to sulphite, and the figures are 

 easily remembered and converted for the preparation of large or 

 small quantities. 



Wenyon (C. M.) & O'Connor (F. W.). The Carriage of Cysts of Enta- 

 moeba histolytica and other Intestinal Protozoa and Eggs of Para- 

 sitic Worms by House-flies with some Notes on the Resistance of 

 Cysts to Disinfectants and other Agents.— J I. R. A. M. C, London, 

 xxviii, no. 5, May 1917, pp. 522-527. [Received 11th June 1917.] 



Amoebic dysentery is caused by Entamoeba histolytica, which, lives 

 in the large intestine, invading the wall of the bowel and producing 

 dysenteric ulceration. The fact of the house-fly being the means of 

 distributing the infective agent has been previously suspected, but 

 it is now established beyond doubt, as the result of experiments 

 conducted by the authors. In the acute stage of dysentery, only free 

 motile amoebae are found in the faeces, but as the acute symptoms 

 abate, smaller amoebae occur and many of these become encysted m 

 transparent capsules, and, as such, are passed in the faeces in very 

 large numbers. Owing to the presence cf the capsule they are 

 relatively hardy structures, and can survive for considerable periods 

 if thev remain moist. These cysts are often passed in very large 

 numbers by " carriers," i.e., cases that have partially, or apparently 

 wholly, recovered from amoebic dysentery. Experiments with the 

 house-flies, Musca and Fannia, and with the blue-bottle, Calliphora, 

 and the green-bottle, Liicilia, have proved that these flies ingest cysts 

 of Entamoeba histolytica when fed on infected faeces, as well as the 

 larger cysts of the non-pathogenic human E. coli, and the cysts of the 

 flagellate, Lamblia intestinalis. This was demonstrated by killing and 

 dissecting the flies immediately after feeding, when the cysts were 

 found in their intestines, where they remained so long as any faeces 

 was present in the gut, in one case as long as twenty-four hours. The 

 cysts seem to escape from the fly only by passing in the faeces and 

 not by regurgitation through the proboscis. With continuous access 

 to human faeces, a fly will feed every few minutes, and as often 

 evacuates its intestinal contents in droplets that contain typical, 

 living, unaltered cysts. Owing to the habit of the fly of cleaning its 

 legs before leaving its food, there seems to be little chance of the cysts 

 being distributed by contact, any that might remain attached being 

 killed by drying, especially under a tropical sun. The most effective 

 disinfectant seems to be cresol of a strength of 1 in 40 or 50, which 

 must be intimately mixed with matter to be dealt with. Much in the 

 way of control can also be done by the careful use of fly-proof latrines 

 and covered receptacles. 



Fermi (C). La Profilassi antimalarica in due Citti sarde. [Antima- 

 larial Prophylaxis in two Sardinian Towns.]— Annali d'Igiene, 

 Rome, xxvii, no. 4, 30th April 1917, pp. 228-236. [Received 

 14th June 1917.] 



This paper describes the antimalarial measures adopted in the 



