10 MASS. EXPERIMENT STATION BULLETIN 319 



on meat infusion agar. On pneumo-agar the organism developed reasonably 

 well, while abundant growth was observed on liver infusion agar. Two types of 

 colonies were observed on pneumo-agar which did not lend themselves to further 

 propagation by transfer, except in one or two instances. The organism exhibited 

 marked pleomorphism. The pleomorphic forms did not stain uniformly, and in 

 some cases the violet color was retained in the Gram stain. Small cells resembling 

 typical 5. pullorum were observed among the larger pleomorphic forms. Visibly 

 infected birds tested with known pullorum antigen possessed a high agglutinating 

 titre. The organism recovered from these birds was agglutinable, and capable of 

 attacking the same fermentable substances as 5. pullorum. 



White (1932) stated that, in addition to the carbohydrate haptenes which 

 characterize the "S" and "R" forms of Salmonella bacilli, an alcohol-soluble 

 protein which he termed "Q" was concerned in the somatic serology of these 

 organisms. This substance was readily extracted by warm acid-alcohol and was 

 a full antigen which stimulated the development of potent precipitating anti- 

 bodies. It occurred in all of the serological types and variant forms of the Salmon- 

 ella group. Besides the ordinary "S" and "R" forms of Salmonella, he referred to 

 rough races derived from strains long cultured in the laboratory, which lacked the 

 "S" and "R" carbohydrate haptenes, and in which no corresponding constituent 

 had yet been demonstrated. These races he designated "p"- forms which aggluti- 

 , nated much more vigorously than did ordinary "R"-forms. The removal of the 

 "Q" fraction markedly reduced the somatic agglutinability of the treated bacilli. 



In 1932 Mallmann reported on dissociation of 5. pullorum and related species. 

 His studies were entirely confined to old stock cultures of 5. pullorum. He classified 

 his strains according to colony form into three groups: smooth, intermediate, 

 and rough. Other colony types, such as mucoid and opaque, were completely 

 ignored. In the investigation he observed two types of variation, the one involving 

 the intermediate form, and the other the smooth and rough forms. The inter- 

 mediate type was found to fluctuate in the direction of either "S" or "R" or both 

 when subjected to different environments, but when the incitants were removed 

 they would return to the intermediate type. In the study of the second type of 

 variation, rough and smooth immune serum broth was seeded with rough and 

 smooth strains, respectively, and incubated at optimum temperatures. Only 

 temporary changes in colony forms were observed. Smooth cultures were changed 

 to partially rough types by exposing them to bacteriophage, and rough types 

 were converted to partially rough types by animal passage. When cultures were 

 maintained in stock on liver infusion agar or gelatin-agar, the various strains 

 tended to return to their normal type. Intermediate strains varied at times 

 from one type to another. Liver infusion agar frequently caused stable smooth 

 types to appear as rough types, but the condition was regarded as purely, transi- 

 torv. Electrophoretic measurements failed to show any significant changes due 

 to animal passage. 



Plastridge and Rettger (1932) reported different colony types of S. pullorum 

 observed on various agar media. Meat and liver infusion agars produced more 

 pronounced rough types than plain meat extract agar. Pleomorphic cellular 

 forms, varying greatly in size, were encountered. Phage-treated strains yielded 

 various colonial and cellular types. The phage action in some instances markedly 

 affected the agglutinating properties of 5. pullorum. A bacteriophage that was 

 highly active against 5. pullorum cells was obtained in extracts of livers and 

 intestinal contents of adult birds surviving an acute attack of the disease. 



White (1933) reported the isolation of a "T" substance from Salmonella bacilli 

 by means of an extracting fluid containing 75 per cent alcohol, sodium chloride, 



