ON THE RELAION BETWEEN THE DEVELOPMENT OF THE HEMOLYTIC STREPTOCOCCI OF THE HORSE AND THE HYDROGON-ION CONCENTRATION OF THE MEDIUM

Abstract

1. The hemolytic zone, which is produced by the hemolytc streptococcus on the blood agar plate, is influenced by the hydrogen-ion concentration of the medium as well as by use of the blood of the horse or rabbit. It is, however, larger as the sizes of pH increase, i. e. on the acid medium it would be smaller than on the alkaline medium. The optimal alkalinity of the medium as it considered on the prodnction of the hemolytic zone is pH 7.5-8.0.2. The hemolytic zone of the βg and βm, both of the atypical strains, as it is produced on the horse blood as well as the rabbit blood agar, has an obscure margin irrespectful of the hydrogen ion concentration. It will, however, become more and more clear as the alkalinity is augumented. That of the typical strains, e. g. βt, has a clearly definable margin irrespectful of the reactions of the medium. It is clearer on the rabbit blood agar than on the horse blood agar.3. The timely relation of the development of the hemolytic zones is: That the time required for the development of the hemolytic zone by βg differs as the horse blood or rabbit blood is employed. On the horse blood agar, having an acid reaction, the hemolytic zone will not cease to grow even after 72 hours of cultivation, but on the alkaline medium, or pH should be 7.5 or more, it will not grow any more after an elapse of 48 hours, the sizes of the hemolytic zone after 72 hours of cultivation will be practically equal to those of the 48 hour old culture. On the rabbit blood agar, Just irrespectful of the reactions as on the horse blood agar, the sizes of the hemolytic zones will grow even after 72 hours of cultivation, the sizes of the zone at the 72nd hour being just eqnal to those of the 48 hour old culture on the horse blood agar.4. The hemolytic zones of the βm strain will not cease to grow even after an elapse of 72 hours irrespectful of the use of the horse or rabbit blood or of the reactions of the medium. The sizes of the zone on the horse blood agar or on the rabbit blood agar are practically the same.5. The strain βt, which had been isolated from the normal horse and a strain which had been isolated from glanders produced each different sizes of the hemolytic zones on the horse blood and rabbit blood agar irrespectful of the reactions of the medium, both of them ceased to grow after 48 hours of cultivation. The sizes of the zone after 72 hours of cultivation on the rabbit blood agar will practically be the same as those of the 24 hour old culture on the horse hlood agar.6. The hemolytic zones on the medium are larger on the horse blord agar than on the rabbit blood agar, which fact may be explained on the differences of the hemolytic power against the homogenous and heterogenous erythrocytes because all the strains I employed for my experiments were isolated from the horse.7. Instrains the common broth, both typical, e. g. βt and atypical, e. g. βg and βm. proliferated just the same, irrespectful of the differences of the reactions. The longevity of the culture on the medium, however, differs as the reactions of the medium is different. On the medium having a larger pH than 7.5, the differences would become more manifest, because on such a medium βg and βm will live 43-47 days, while the βt strain will live only 3-5 days.8. The pnoliferation and longevity of both typical and atypical strains on the 1.0-0.5% glucose-brototh agreed with each other. In the 0.1% glucose broth, however, there were met with certain differences concerning the proliferation and longevity of each different strains.9. Both the typical anb the atypical strains of the hemolytic streptococci of the horse proliferate very good in the common and the glucose broth having the pH of 7.5 and 8.0. Although the pH indices would be a little higher, the same good proliferation would be the result,