3 i4 TYPHOID FEVER. 



by Koch to overcome the same difficulty in the case of the 

 cholera vibrio, namely, the neutralisation of the gastric juice 

 with soda before the introduction of the bacteria, and the 

 slowing of the intestinal peristalsis with opium (vide chapter 

 on Cholera). These observers succeeded by this method 

 in causing death in rabbits and guinea-pigs. They, as well 

 as others, also caused death by intraperitoneal, intravenous, 

 and subcutaneous injections of pure cultures. In animals 

 thus inoculated there were, in a few hours, restlessness, 

 swelling of the abdomen, pyrexia, and gradually increasing 

 weakness, with death in twelve hours to four or five days. 

 Post mortem there were swelling of the spleen, congestion 

 of the liver and kidneys, hyperaemia especially of the upper 

 part of the intestine. Some observers found swelling and 

 even occasionally ulceration of Peyer's patches. The typical 

 typhoid lesions, however, were not reproduced. The dis- 

 tribution of the bacilli varied with the seat of introduction. 

 If introduced into the blood stream they were found through- 

 out the body, but especially in the spleen ; if introduced 

 into the peritoneum they were found chiefly in the spleen 

 and liver. Sirotinin showed that dead cultures produced 

 the same effects, and Wyssokowitch observed that living 

 bacilli injected into the peritoneum rapidly decreased in 

 numbers, though still present, e.g., in the spleen. Many, 

 therefore, held that there was no evidence that the bacilli 

 multiplied in the blood, and considered that the effects 

 were due to toxic bodies injected along with the bacilli. 

 Other observers did not confirm Sirotinin's results with the 

 injection of dead cultures, and Pfeiffer is probably correct 

 in holding that the diverse results obtained were due to 

 differences in the virulence of the cultures used. Such 

 differences in virulence can be produced artificially, and an 

 artificial exaltation of this virulence forms the basis of the 

 important work of Sanarelli. 



Sanarelli starts with the statement that most ordinary 

 laboratory cultures are either entirely non-pathogenic, or 

 pathogenic only on the intraperitoneal injection of large 

 doses. The virulence can be exalted in various ways. He 



