Abstract
The purpose of this study was to observe the behavior of skin tests under the conditions of experimental arthritis. One of the questions which a clinical study of chronic rheumatism presents is whether a joint once infected can in itself be a focus from which further exacerbations of the disease may arise. Accordingly, in arranging the experimental conditions under which the subject of bacterial allergy was to be studied, arthritis was produced not only by inoculating animals intravenously but also by inoculating small amounts of bacteria into the joints. The organism used was a laboratory strain of hemolytic streptococcus, preserved by freezing and desiccating the culture. Skin tests were made on the backs of the rabbits, after the hair had been clipped and removed with sodium sulfide. This depilatation was carried out 2 to 3 days before the skin tests were made. The toxic filtrate used was prepared by seeding a 24-hour broth culture of the organisms into about 100 cc. of Harley's toxin media. This was incubated for 5 days, centrifugalized and filtered through a Berkefeld candle. Normal rabbits were found to give no skin reaction following the intradermal injection of 1/10 cc. of these filtrates. Animals so tested were used in these experiments. In the series reported 24 animals were used, the same number being inoculated intravenously as by the intra-articular route.
After intravenous injection, rabbits usually develop a positive blood culture. Daily blood cultures then show one of two things. The animal tends to recover and the daily blood culture shows fewer and fewer organisms, or the animal grows rapidly worse with more and more organisms per cc. of blood and soon dies. The rabbits surviving may or may not develop metastatic joint infections.
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