This investigation is very limited and the number of patients treated is few, yet the following conclusions may not be amiss:—
1. The vaccine in no instance did harm, and the reactions in the majority were very mild and of short duration.
2. Cases in which bacteriologically B. dysenteriæ were proved to be present, but in a clinically unrecognizable form, were not affected differently from those which were culturally negative. This may in part be due to the fact that this mode of vaccination produces an immediate passive immunity, while the bacterial vaccine is producing an active immunity.
3. The work is of interest and holds out a possible means of preventing the great mortality from infantile dysentery during the summer months.