In carrying out some experiments involving the injection of living typhoid bacilli in rabbits and the plating several hours later of the rabbits' blood in nutrient agar, we observed that some of the colonies developing upon the plates showed spontaneous agglutination when rubbed up in a drop of saline solution upon a glass slide. A number of the colonies were fished into small tubes of nutrient broth and after twenty-four hours' incubation yielded, instead of the usual turbid growth characteristic of the typhoid bacillus, flocculi throughout the broth and a flocculent sediment. We at first thought that this change in the typhoid strain had been brought about by its sojourn in the body of the rabbit; however, upon plating the original typhoid culture and fishing a number of the colonies into broth we observed a similar type of growth in some of the tubes.

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