THE COLON -TYPHOID GROUP 103 



Mild typos of the disease arc as likely to give rise to bacilli 

 carriers as the severest forms. Typhoid carriers may also 

 be recruited from those who have not passed through an 

 attack of the disease in a clinically recognisable form and 

 from those who have been in contact with typhoid cases. 

 The handling of food by such persons is a great source of 

 danger, and outbreaks of the disease have been definitely 

 traced to them. 



Serum-Therapy. Chantemesse grows the typhoid 

 bacillus in a maceration of spleen, bone-marrow, and 

 defibrinated human blood. This, on the injection of an 

 animal, produces a serum which, Wright suggests, perhaps 

 owes its value to the presence of toxins and not of anti- 

 bodies. Macfadyen and Hewlett, by injecting horses 

 with the cell- juice of typhoid bacilli, prepared by grinding 

 the bacilli in the presence of liquid air, obtained a serum 

 of promise. 



Anti-Typhoid Vaccine (Wright). Typhoid bacilli (the 

 virulence being kept by intraperitoneal passages through 

 guinea-pigs) are grown in nutrient broth in flasks, at 

 37 C., for a maximum period of thirty-six hours, and not 

 that of ten to fourteen days as formerly. A temperature 

 of 60 C. as originally employed for killing the bacilli 

 seriously affected the keeping property of the vaccine. 

 Now, after the contents of several flasks have been mixed 

 (to get a uniform product), the culture is killed by exposure 

 to 53 C. for an hour. Portions for testing sterility by 

 both aerobic and anaerobic methods are removed and the 

 bulk is allowed to cool, when 4 per cent, of lysol is added. 

 (Addition of lysol to the hot vaccine destroys the immun- 

 ising properties.) This killed culture forms the vaccine, 

 which is standardised by estimating the content of bacilli 

 (see p. 24). A dose of 500 million is injected subcutane- 

 ously, and is followed by a febrile reaction, which soon 

 passes off. To obtain more complete protection a second 

 injection of twice the original dose may be given after an 

 interval of ten to fourteen days. The success of this 

 vaccine is remarkable both as a prophylactic and as a 

 curative measure, and an expectation that it will clear 

 the organism from carriers appears reasonable. In the 

 Expeditionary Force in France the ratio of attacks is 

 fourteen times and of deaths forty-two times greater 

 among the uninoculated men. The vaccine loses its 



