CH. ix] OF TRANSMUTATION 119 



the urine of typhoid carriers, intermediate in character between 

 B. typhosus and B. coli. Wilson (1910) described such an 

 organism as fermenting glucose and mannite but, unlike B. ty- 

 phosus, fermenting lactose also at 22 C. (but not at 37 C.) 

 and failing to agglutinate with typhoid serum. The Bacillus 

 perturbans of Klotz (1906), though agglutinated by high dilu- 

 tions of typhoid serum, fermented lactose and saccharose, 

 gave the neutral red reaction and produced indol. 



Examples have also been given (vide Chapter V) to show 

 the variability of organisms with respect to their power to 

 ferment sugars and their ability to acquire fresh fermenting 

 properties. B. typhosus, for example, may acquire the power 

 in a few days to ferment dulcite. 



The organism described here by Major Horrocks is another 

 example of temporary variation in character with respect to the 

 power to ferment sugars and to produce indol, associated with 

 some modification also in agglutination properties. 



(&, c) The change from B. typhosus to B. faecalis alcaligenes 

 due to symbiosis with B. coli. 



(Page 233, exp. 1.) The strain of B. typhosus used was 

 a stock laboratory strain " R," from which stock vaccines were 

 prepared a strain, that is to say, of unimpeachable character. 

 The strain of B. coli was derived from the urine of a typhoid 

 carrier ("Bomb S "). The two organisms were added to 1 c.c. of 

 sterilised tap water and the suspension plated. 10 days later, 

 examination showed typical typhoid colonies and others white 

 and opaque. The latter were planted on the usual media and 

 in 48 hours yielded slight acidity in mannite only ; no other 

 sugars were fermented in 7 days. The original strain of B. 

 typhosus used was replanted on agar and the resulting growth 

 gave the typical reactions of this organism. 



(Page 234, exp. 3.) The experiment was repeated, a dif- 

 ferent typhoid strain ("Bombay ") being used. After an interval 

 of two months, 1 c.c. of the inoculated water was added to 

 MacConkey's bile salt broth and this plated on lactose bile 

 salt litmus agar. A few blue colonies were seen consisting of 

 bacilli which resembled B. faecalis alcaligenes in not ferment- 

 ing any sugars and producing an alkaline reaction in milk. 



