Further Experiments, &c. By Dr. B. L. Maddox. 943 



that I might have at hand a supply of the pure comma bacillus, 

 and afterwards also furnished me with other uninoculated tubes, in 

 order, if required, I might be able to complete my experiments. 



Having for several days satisfied myself, by microscopical ex- 

 amination, of the non-existence of any comma or curved bacillus in 

 the natural excreta of Eristalis, two of the insects, by way of con- 

 trol experiment, were put into captivity on the plan described in my 

 former paper, and fed on a small freshly-cut lump of sugar, 

 moistened with a recent watery solution of methyl-violet. On the 

 19th of July, that is twenty-four hours after, the first of the 

 coloured dejections were examined, and found to contain numerous 

 pollen-grains, small, straight, non-motile rods with blunt ends, 

 bacteria and micrococci amongst much debris, but no curved rods. 



On the 20th four similar insects were placed together in like 

 captivity, and the dejections passed upon the square of glass before 

 they were fed with a gelatin culture of the comma bacillus on sugar, 

 were examined with a result agreeing with that of the control insects. 

 Half an hour after being fed several dejections were noticed of a 

 pale yellowish colour ; on examination no curved bacilli could be 

 found. On the 21st, about eighteen hours after being fed with 

 the gelatin culture, nine dejections that had been settled on the 

 glass were by a sterilized needle mixed in a droplet of freshly-boiled 

 distilled water. Amongst the other organisms in the quantity ex- 

 amined only five motionless curved bacilli could be found in many 

 fields. The plan adopted was to examine the excreta moistened, 

 also dried, unstained and stained, and the stained counted for the 

 numbers described, though the unstained wet and dry often fur- 

 nished, as far as could be judged, higher figures ; movement in the 

 wet unstained slides was accepted as evidence of life. This plan 

 was adopted throughout the experiments. On the 22nd, twenty- 

 seven spots were mingled and examined ; the curved bacilli were 

 rather more numerous, but none seen in motion. There were only 

 seven dejections on the 23rd, they afforded still a few commas, and 

 one of these had a perceptible though slight motion, and in the 

 excreta were very great numbers of minute oily-looking globules. 

 Nineteen spots were examined on the 24th, the curved bacilli were 

 very few, and only one seen to be active. A little alteration was now 

 made. To the sugar, after damping with the gelatin culture, was 

 added a droplet of freshly boiled distilled water, as the original 

 culture appeared to dry up too soon. On the 25th there were 

 seventeen dejections, these were passed on two squares of glass, as 

 the insects by continually treading over the dejections seemed to 

 weaken the number of microbes. The commas were still very rare, 

 and it was doubtful if they were living. The pollen-grains had 

 disappeared, the small straight bacilli were much less numerous, 

 but the oily globules and micrococci had increased. The insects 



