In order to search for the source of staphylococci responsible for food poisoning, studies were made on some properties of staphylococci isolated from rats (Rattus norvegicus) and swine, both of which had close relations with human beings. These staphylococci had been isolated from the nose of swine and the skin of rats. Coagulase-positive staphylococci were derived from 65 (50%) of 130 rats and 58 (85%) of 68 swine. These isolates were proved to have the following biological characters, drug sensitivity, and phage type.
1. All the strains of coagulase-positive staphylococci isolated from rats and swine produced DNase, phosphatase and lysozyme, and reduced nitrate.
2. Only 34 percent of the coagulase-positive strains isolated from rats showed β hemolysis, while almost all the strains (97%) isolated from swine were β hemolytic.
3. The biological properties of the strains of rat origin were not always the same as those of swine origin. There were differences between the two in such respects as colonial color, lipase production, gelatin liquefaction, coagulation and later peptonization of litmus milk, hydrolysis of esculin, and egg reaction.
4. Forty percent of the strains of rat origin were relatively resistant to penicillin, showing a susceptibility higher than 25u/ml. Thirty-five percent of the strains of rat origin and 83 percent of those of swine origin were relatively resistant to streptomycin (susceptibility higher than 12.5mcg/ml). Only 13 percent of the strains of swine origin were relatively resistant to tetracycline (higher than 12.5mcg/ml). About 80 percent of the strains isolated from both animal species were resistant to sulfathiazole (higher than 100mcg/ml). All the strains tested, however, were sensitive to chloramphenicol, oleandomycin, and erythromycin (less than 6.3mcg/ml). All the strains that were relatively resistant to penicillin and streptomycin formed yellow colonies on solid medium and were proved to be α hemolytic.
5. Typing was carried out on these isolates using the basic set of typing phages which has been selected by the International Committee. Eighty-one percent of 58 strains of swine origin were successfully typed. Three-fourths of the strains which had been typed by this set of phages showed susceptibility to group II, and the rest of them belonged to the mixed group. On the other hand, only 17 percent of the strains of rat origin was found to be typable and belong to group III without exception.
6. It can generally be mentioned that the properties of some of the strains of rat origin were closely related to those of the strains isolated from the cases of staphylococcal food poisoning, while the strains isolated from swine were considerably different from those from human beings.
From these results, it is quite probable that the rat is playing an important role as a source of contamination in the case of staphylococcal food poisoning.

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The strains of Escherichia coli resistant to kanamycin (KM), chloramphenicol (CM), tetracycline (TC), streptomycin (SM), or sulfonamide (SA) were screened from the faces of 200 in-patients affected with pulmonary tuberculosis.
1) The patterns of drug-resistance in the strains were SM⋅SA (30%), TC⋅SM⋅SA (21%), SA (21%), CM⋅TC⋅SM⋅SA (16%), and others. No strains resistant to KM were isolated from any patient who had never been treated with KM.
2) In patients administered with KM, the isolation frequency of KM-resistant strains from E. coli was lower than that from Mycobacterium tuberculosis.
3) In seriously ill patients, their intestinal flora underwent gignificant changes and few drug-resistant E. coli strains were isolated.
4) A total of 57 R factors were obtained from 101 drug-resistant strains of E. coli. Of them, R (CM⋅TC⋅SM⋅SA) and R (SM) were isolated most frequently.

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A study was made on the ontogenetic development of humoral immunity derived from the bursa of Fabricius in chickens. The dynamics of hemolytic plaque-forming cells (PFC) were investigated following intravenous injection with sheep erythrocytes. Experiments were carried out on the effects of transfer of the bursal and splenic cells in “bursaless” birds. The following findings were obtained.
1) Immunocompetent X-cells, i.e. the progenitors of PFC-producing hemolytic antibody, appeared in peripheral lymphoid tissue 5 days after hatching, and continued to show a rapid increase until about 2 weeks of age. Thereafter, the relative number of X-cells among the lymphoid cells was at a constant level during the remaining period of development. However, the absolute number of X-cells continued to increase with growth of the lymphoid organs. Be the matter as it may, it has been verified that the immunological maturation can be expressed as an increase in bursa-dependent X-cells.
2) Acomplete loss or suppression of the humoral antibody-producing capacity of “bursaless” chickens was not due to a disorder of antigen-processing activity of macrophages responsible for antigenic information, but due to the absence or decrease of X-cells in peripheral lymphoid tissue.
3) Although the bursal lymphoid cells acquired immunocompetence in situ by a still unknown mechanism, they were not directly involved in the immune response of antibody production. It was confirmed that they had migrated into the peripheral lymphoid tissue in neonatal life and then functioned as X-cells, which proliferated and differentiated in response to antigenic stimuli and turned to antibody-producing cells.

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