Abstract
Arnold 1 reviewed the work done in this laboratory upon the permeability of the intestinal tract to bacteria as a result of certain environmental changes. This is a report of our attempt to utilize similar experimental procedures to determine the permeability of the intestinal tract of the dog for B. tuberculosis.
Young dogs (2 to 4 months old) were used for these experiments. Some animals were given doses of B. tuberculosis in milk and placed upon a general bread and milk diet for 4 weeks. Others were fed a dose of B. tuberculosis and killed between 1 and 2 hours after feeding. A third experiment consisted of injecting the B. tuberculosis directly into the lumen of the duodenum and examining certain tissues 30 minutes later. The mesenteric lymph gland was removed from all dogs immediately after killing them in the ether chamber. The gland was macerated by grinding in mortar with sand and 3% sodium hydroxide, neutralized with hydrochloric acid and injected into 2 guinea pigs.
Forty-five young dogs were fed 3 times, once daily for 3 days, 10 mgm. B. tuberculosis in 100 cc. milk. Fifteen animals were given plain milk (pH 6.7) 8 of these were in ordinary temperature rooms, 7 were in warm and humid rooms (90° F. and 90% relative humidity); the same experiment feeding lactic acid milk (pH 5.0) and feeding alkaline milk (pH 8.0). These animals were observed for 6 weeks. Six died during this time, all had B. tuberculosis in mesenteric lymph gland by guinea pig test. These 6 puppies were undernourished and in poor condition at the beginning of the experiment. Only 3 of the remaining 39 animals showed positive B. tuberculosis by guinea pig tests.
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