FATE OF ORGANISMS EATEN BY LARVA II5 



"On August 22ud two ounces of liquid feces, containing B. paratyphosus K, were 

 put into a box of earth and about 30 flies allowed to feed on it ; as the flies had no 

 water given to them they died in a day or two. On September ist one fly hatched 

 out ; on September 3rd 1 2 flies were seen. On the same date the earth was replaced 

 by a plate as before. On September ist one fly, one day old, was examined ; the 

 McConkey control was negative ; and after being flamed and crushed B. paratyphosus 

 A was obtained. On September 3rd four flies, each one day old, were examined ; the 

 McConkey control was negative ; and from the crushed flies B. paratyphosus A was 

 separated. On September loth 3 flies, each seven days old, were put through the 

 sterile bottle test, the excrement was examined, and from it B. paratyphosus A was 

 obtained." It was also obtained from the crushed flies. "On September 13th one 

 fly, 10 days old, was examined, but the bacillus was not recovered. Two other flies, 

 also 10 days old, were examined and B. paratyphosus A was recovered." 



These very suggestive experiments have influenced several 

 workers to make observations on the same Hnes, and their 

 experiments are recorded in the order of publication. 



Bacot (III. 1911) experimented with Musca doniestica and 

 B. pyocyaneiis. 



" About an inch of dry silver sand was placed in a one-pint card cream jar. A 

 mixture consisting of cooked meat, baked rice, rice pudding, custard, boiled potato, 

 gristle of meat, was chopped up, and, together with the contents of several agar tubes 

 of pure cultures of B. pyocyaneus, was placed on the sand, ova of Musca domestica 

 being added. By the time the larvae were from half to two-thirds grown, the food 

 was exhausted, so a small quantity of lean uncooked beef was minced, wetted with 

 distilled water, mixed with the contents of a tube of pure B. pyocyaneus and allowed 

 to remain at 29° C. for three or four hours. It was then given to the larvae. When 

 the larvte were full fed, all remnants of the food were removed and some clean sand 

 added at the bottom of the jar." 



Twelve of the pupae -obtained were placed in lysol (5 — 10%) for 5 to 7 minutes. 

 Then transferred to a tube of broth and shaken up. The time of immersion in this 

 medium varied between five minutes and 13 hours. Afterwards they were removed 

 to a second tube of broth and broken up with sterile needles. In all cases the second 

 broth tube gave a copious growth of B. pyocyaneus, showing that this organism was 

 present within the pupte and in several cases the first broth tube gave a slow growth 

 of the organisms, probably indicating that some communication exists through the air 

 passages. 



Ten flies which emerged from pupse were also examined. Four were placed in 

 5 "/o lysol, and then washed in a tube of broth and then transferred to a second tube 

 and broken up. On incubation the second tube gave a marked growth and the first 

 tube a slow growth. Five flies were treated with 5 % lysol, and after being washed 

 in two successive broth tubes broken up in a third. Only the latter gave growths on 

 incubation. Lastly a fly was seen to emerge, and removed to 5 "/^ lysol before it had 

 any opportunity of infecting itself. Thence it was passed through a broth tube and 

 broken up in a second. Only the latter gave a growth of B. pyocyaneus. 



From his experiments the author comes to the following 

 conclusions: — "(i) Pupai and imagines oi Mtisca domestica bred 



