264 THE AMERICAN MONTHLY [Sept 



some time, and seemed tome to be considerably affected by 

 the food, but as two of the four illustrations refer to the 

 blowfly, which is fairly hardy in captivity, one being set 

 at liberty after forty days confinement, and fed for many 

 days on the cultures, the remark will refer chiefly to thai 

 insect. 



For the main particulars of the experiments I beg to 

 refer to the aforenamed articles in the Royal Microscopical 

 Journal. The insects were generally captured by placing 

 a prepared tumbler over the insect, and then sliding stiff 

 paper or card-board beneath and transferring the vessel 

 to a clean and shallow saucer or plate of glass on which 

 a square piece of glass was placed. This served to col- 

 lect the dejections passed on it, and was easily removed to 

 substitute another on which a small lump of sugar,damp- 

 ened with the culture, sometimes diluted, was afterwards 

 placed. The microscopical examinations were made after 

 scraping up the excreta passed at various periods extend- 

 ing even to thirty-six hours and comprising thirty-one 

 dejections, by a flattened needle, and mixing them with 

 sterilized water on a cover-glass. There was one difficul- 

 ty originated by this plan which I fancy led to many of 

 the experiments being abortive, as many of the dejec- 

 tions were dried up, and the contained bacilli probably 

 dead, or killed sometimes by the high temperature. 



Before touching the details it may be as well to state 

 that Dr. Grassi found in 1883 that flies which had fed on 

 the ova of Taenia solium that had been kept in alcohol, 

 passed dejections containing the ova ; also that others 

 which had fed on the ova of a Tricocephalus from a plate 

 in the laboratory, carried and deposited the ova on pieces 

 of paper placed in the kitchen. Dr. Grrassi also found 

 they could be carriers of the ova of the thread worm, 

 Oxyuris. I think that lately experiments have been 

 made of a more extended nature iu the same direction 

 with the plague bacillus, but unfortunately I havp no data 



