152 BACTERIOLOGY 



a small number of indifferent varieties develop on this 

 medium, while the typhoid bacilli grow characteristically. 



Parietti adds to several test-tubes, each containing 

 10 c.cm. of neutral bouillon, from three to nine drops of a 

 hydrochloric acid phenol solution (4 grms. hydrochloric and 

 5 grms. carbolic acid to 100 grms. water), deposits them for 

 twenty- four hours in the incubator, and then treats them 

 with one to ten drops of the water under examination. If 

 turbidity is visible after another twenty-four hours' standing 

 in the incubator, it may be concluded with certainty that 

 typhoid bacilli are present. 



Intravenous injections kill rabbits in about twenty-four 

 hours, when the bacilli may be detected in the urine, blood, 

 and excreta. 



Infection takes place principally by means of water 

 contaminated with the bacilli, but also by contaminated 

 milk and linen. The microbes are capable of effectually 

 resisting the action of the gastric juice, and as soon as they 

 reach the intestinal canal they penetrate into the lymphatic 

 canals and are carried by the stream of lymph into the 

 other organs, particularly the [mesenteric glands] spleen and 

 liver. Eberth has shown that they may penetrate into the 

 placenta, and in this way reach the foetus. 



[The typhoid bacilli have also been found in the 

 blood, not only in the rose spots (Neuhauss) but in the 

 general circulation, having been detected in blood from the 

 finger.] 



Bacterium coli commune. Eodet and Koux found this 

 bacterium in the water of localities where typhoid was 

 prevalent, and it has been constantly met with by Escherich 

 in the intestinal canal of suckling infants. It consists of 

 short, slender rods possessing a sluggish motility, which 

 occur sometimes singly and sometimes in pairs, and which 

 are decolorised if treated by Gram's method. Gelatine is 



