THE COLON-TYPHOID GROUP 101 



insects, and should any be swallowed they may pass 

 through the fly unhurt. Living bacilli have been found 

 in or on the bodies of flies twenty-three days after infec- 

 tion. Dutton infected two healthy persons by exposing 

 them to bed-bugs that had previously bitten a typhoid 

 case. 



Vegetables. Watercress grown in sewage-polluted 

 streams, and vegetables from sewage farms, are proved 

 to have been the means for the conveyance of the disease. 

 Creel ascertained that plants from seed sown in infected 

 soil carried typhoid bacilli on their leaves for over thirty 

 days when shade was provided. In full sunlight the 

 t3^phoid bacilli lived ten days at the outside. 



Soil. Whereas in peat the bacillus dies within twenty- 

 four hours, in moist earth it may exist for two or three 

 months, but shows no tendency to increase in numbers. 



Milk. Through being handled by infected persons, 

 through the use of polluted water for rinsing out utensils 

 or for purposes of dilution, typhoid bacilli can obtain 

 access to milk, and it is probable that multiplication may 

 take place. The organism will survive for at least twenty 

 days, even after the milk has turned sour and curdled. 

 Butter made from infected milk retains the power of 

 infection for a time, and it is possible that the organism 

 may exist in curd cheeses. A series of cases on the round 

 of a specific milkman is the usual clue to the origin of 

 a milk epidemic. There is no evidence to warrant a 

 suggestion that cows may suffer from and transmit the 

 disease. 



Filters. A filter such as the domestic carbon type, 

 which only arrests a portion of the micro-organisms, if 

 contaminated by the passage of an infected water, will 

 continue to infect water passing through it, even if this 

 be pure. 



Contact. Direct infection of a healthy person by a 

 typhoid case is not uncommon. The ' typhoid carrier ' 

 (vide infra] is especially dangerous on account of his 

 condition being probably unrecognised. 



Pathogenesis. The bacillus can nearly always be found 

 in the blood during the fever period, the number being 

 greatest during the early stages of the fever. The 

 number decreases with the temperature, and disappears 

 when the latter reaches normal. Inflammation and 



