300 KAN-ICHIRO MORISHIMA 



isolated from human cases, and emphasizes the diagnostic difficulties 

 which this may occasion. Bull and Pritchett (1916), however, repeating 

 the work of Gay and Claypole found that 25 generations of cultivation 

 in separate series upon plain agar and upon blood agar did not produce 

 appreciable agglutination differences in a typhoid strain. They carried 

 this out with 57 different strains of typhoid bacilli. Nichols too has 

 contradicted the claim of Gay and Claypole that gall bladder infec- 

 tions could be regularly produced in rabbits by injection of typhoid 

 strains grown on blood agar, an observation which would further 

 strengthen the opinion of a fundamental change in reaction to the ani- 

 mal body and its fluids produced by cultivation upon blood constitu- 

 ents. Our own observations (in which we cultivate the typhoid strains 

 upon normal rabbit's serum) also indicate that such a procedure does 

 not exert any appreciable effect upon their agglutinability. Thus the 

 results of Gay and Claypole concerning the inagglutinability of cul- 

 tures obtained from infected human beings and rabbits would corre- 

 spond in principle with the investigations of other workers. But 

 the alterations obtained by them by simple growth upon normal blood 

 agar cannot be accepted as conclusive in the light of contradictory 

 results of Bull and Pritchett and of Nichols, and also in the light of our 

 own failure to obtain appreciable changes in strains carried for many 

 generations on normal rabbit serum broth. 



It appears from these researches (and many others which 

 might be cited) that the problem has not yet been solved in all 

 particulars. But the general weight of evidence indicates that 

 cultivation in the presence of specific serum antibodies alters 

 the strains in the direction of lessened agglutinability. 



The following experiments upon this phenomenon were carried 

 out by us: 



Materials used in agglutination tests 



1. Broth. This consisted of 0.1 per cent Liebig's meat extract; 1 

 per cent pepton (Difco ); and 0.5 per cent sodium chloride per hter; 

 its reaction was adjusted to pH 7.0. It was sterilized in the autoclave 

 at 15 pounds pressure for fifteen minutes. 



2. Antityphoid serum from rabbits immunized against monovalent 

 strain of typhoid bacilli (Rawlings, C-51, no. 3, Cohen, C-188). Each 

 serum titre was 1:10,000 or 1:20,000 for our standard laboratory 

 strains. 



