Aug. 19, 1922] SECTION OF MICROBIOLOGY. [MJrcALjo'uTKAL 



the Local Government Board in 1915, similar experiments were carried out with 

 material obtained from the intestinal tract. After certain difficulties had been 

 overcome it was found that in the upper third of the intestine, which contained 

 numerous bacilli of the colon group, some larger forms were also present. In 

 some cases these grew in far greater number than the ordinary types of bac- 

 teria, but this was only so when precautions were taken to eliminate the action 

 of a dissolving substance which infected the colonies so rapidly that they were 

 dissolved before attaining a size visible to the eye. Here, then, was a similar 

 condition to that found in vaccinia, and the greatest difficulty was experienced 

 in obtaining the bacilli free from the transparent dissolving material, so rapidly 

 was the infection increased and carried from one colony to another. At first 

 this bacillus was not believed to be a member of the dysentery-typhoid-coli 

 group, but I have now no doubt that it was a special large form of a member 

 of this group. Unfortunately 1 lost my cultures during the war before all the 

 characters of the bacillus were completely worked out. 



Similar though not such definite results were also obtained with a micro- 

 coccus and a member of the coli-typhoid group of bacilli which were obtained 

 from the intestinal mucous membrane of a dog sufiFering from acute distemper, 

 and I obtained some evidence that the difficulty often experienced in isolating 

 certain known pathogenic micro-organisms might be due to the same cause. 

 In my paper I also pointed out that results similar to those obtained with 

 vaccinia and with bacilli from the intestinal tract would probably be obtained 

 in cases of true dysentery; but I was unable at the time to investigate dysen- 

 tery, as my scheme for research on this disease which was submitted to the 

 War Office in 1914 was not accepted. Shortly after the publication of my 

 work, however, I went to Salonica in charge of the base laboratory. While 

 there in 1916 the subject was again discussed on several occasions with the 

 English, French, and Canadian bacteriologists; but at the time the phenom- 

 enon was not accepted as one of much importance, and my fresh proposals 

 for continuing the work on dysentery failed to meet with approval. As, how- 

 ever, I had predicted, a similar condition was later found to occur in cultures 

 of true dysentery bacilli, particularly by Dr. d'Herelle, who carried out a 

 series of important experiments on these bacilli. Dr. d'Herelle's published 

 researches appear to me to confirm in the main my own results with micrococci 

 and members of the coliform group of bacilli. 



I will now pass on to consider the conclusions I drew from mv experiments. 

 In the case of vaccinia it is clear that the transparent material contains an 

 enzyme, and this is destroyed on heating to 60° C. for one hour. It also 

 increases in quantity when placed on an agar tube containing the micrococcus, 

 and this can be carried on indefinitely from generation to generation. If it is 

 part of the micrococcus it may be either a stage in its life-history which will 

 not grow on ordinary media but stimulates fresh cultures of the micrococcus 

 to pass into the same stage, or an enzyme secreted by the micrococcus which 

 leads to its own destruction and the production of more enzyme. The fact that 



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