Abstract
Cultures of the gas bacillus which have been enriched with carbohydrate utilizable by the microbe for its energy requirement, contain a substance, possibly substances, which will both induce immediate contracture in isolated guinea pig small intestine immersed in Tyrode solution according to the Trendelenburg technique, and also cause a pronounced, but rather transient, depression of blood pressure in the dog under ether anesthesia upon intravenous injection. The potency of the average 48-hour culture is such that from 0.05 to 0.4 cc. of the fluid medium, freed from bacteria by passage through a Berkefeld filter, will cause such strip of intestine, less than 5 cm. long, preferably from the ileal region, attached to a suitable lever with an arm ratio of 1:9, to record a contracture from 5 to 12 cm. high. Two cubic centimeters of such a filtrate will induce a rather transient drop of some 40 per cent in the blood pressure of a dog weighing about 24 kilos.
The ratio of cultures used to Tyrode solution is from 0.05 to 0.4 cc. of the former to 125 cc. of the latter; and in the dog not greater than 1:1000 of the total blood volume. These effects are elicited by the unaltered, entire, bacteria-free solution which contains much water and other material. The reactive substance is readily washed out from the contracting substance by simply replacing the solution containing it with a fresh Tyrode solution. The actual amount of reactive substance is a very small fraction of the material used for experiment.
The occurrence of the reactive substance is not limited to one or two selected strains of the gas bacillus: some 72 cultures, obtained from the intestinal contents of 41 persons have been studied.
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