280 KAN-ICHIRO MORISHIMA 



generations on ordinary pepton agar. His conclusions were that the 

 sugar fermenting powers of an organism may be artificially changed 

 by growing the said organism for a succession of generations in media 

 containing a sugar which at the commencement of the experiment it 

 was unable to ferment. 



Kuwabara (1907, 1909) under the direction of Dr. Shiga isolated an 

 atypical typhoid in addition to a typical one from a typhoid patient's 

 stool. It fermented lactose, sucrose, and milk-whey as Bad. coli does 

 and produced reddish color on Endo and Conradi-Drigalski plates but 

 agglutinated in antityphoid rabbit serum in high dilutions just as a 

 normal culture of typhoid bacilli did. After twelve to fifteen passages 

 through plain laboratory nutrient media these atypical characters all 

 disappeared. 



The results of Twort and Kuwabara amount practically to a 

 complete alteration of the identification characteristics of the 

 typhoid bacillus. These observations are of the greatest theoreti- 

 cal importance but fortunately strains of this nature have been 

 produced or observed so rarely that they cannot be regarded 

 as a practically important factor of confusion in identification. 

 This is apparent from Penf old's work cited below\ 



Penfold (1910a, 1910b, 1911, 1914) as cited by Dixon, working with 

 twenty strains and carrying many of them for more than a year in a 

 lactose medium, obtained only negative results; he showed that the 

 Twort lactose fermenting strain gave rise to daughter colonies on lactose 

 agar. This Twort culture fermented sorbitol in broth only after a 

 number of days and Penfold found that it also gave rise to daughter 

 colonies on sorbitol agar. He observed with some of his cultures late 

 acid production in rhamnose broth and on transplanting from rhamnose 

 broth to rhamnose broth after several weeks of incubation, he was able 

 to obtain subcultures which fermented in one, two or three days. He 

 also made a very careful study of the behavior of Bad. typhosum in 

 dulcitol broth and on neutral red dulcitol agar. In one of his experi- 

 ments in which fourteen strains were inoculated into dulcitol broth the 

 first signs of acidity occurred in from five to fifteen days. If, after one 

 month, subcultures were made in new dulcitol broth, an acid reaction 

 was produced in from one to four days. Subcultures, which had been 

 trained to ferment dulcitol rapidly showed great permanency; one such 

 culture transplanted twenty-five times in pepton water during a period 



