The localization of Bacillus proteus × 19 in the subcutaneous tissues of the guinea pig by means of preliminary injections of carbon at different intervals.

Abstract

1. The subcutaneous injection of Bacillus proteus × 19 into guinea pigs caused death from acute septicemia in a considerable percentage of cases; when a suspension of carbon was simultaneously introduced the mortality was definitely reduced, but when the injection of carbon preceded that of the bacteria by an appreciable interval this initial mortality was reduced to zero in a series of 61 animals. In an additional group of 9 animals in which the carbon and proteus were injected together there were no deaths, but among 21 guinea pigs in which the organisms were introduced without carbon, there were three deaths from septicemia.

2. The only obvious explanation for the absolute protection afforded these animals is a mechanical one, viz., a blockade of the lymphatic drainage of the injection site.

3. The protection given by the lymphatic blockade is evidently a relative one, and depends more or less upon the limitation of the organisms to the injection area. Invasion of the blood stream, even in sub-lethal doses, was observed only in 7 instances, 4 in which the injection of carbon preceded that of the proteus by an interval of less than five hours, 1 in which the two suspensions were given simultaneously and 2 in which the organisms were injected alone. Complete protection was apparently afforded when the interval was sufficiently long, i. e., five hours or more, allowing complete obstruction of the lymphatics to take place. The bacterial suspension evidently diffused some what beyond the actual point of injection, but was really limited by the obstruction of lymphatics over an area somewhat larger than that in which edema could be observed. Lines of carbon were seen stretching as far as 2 to 3 cm. from the point of actual injection.