THE BACILLUS OF TYPHOID FEVER 311 



would appear that excess or deficiency of moisture in soils is the 

 dominant factor affecting the chances of survival of the typhoid 

 bacillus in, or at least the possibility of recovering it from, soil. 

 Presence or absence of organic matter, upon which previous 

 workers have laid great stress, is apparently of less importance to 

 the issue. From these facts Firth and Horrocks conclude that the 

 typhoid bacillus is able to assume a vegetative or saprophytic 

 existence for considerable periods outside the body.^ It is evident 

 soil may receive very massive pollution from typhoid dejecta, and 

 thus set up for a long period of time a sort of potential infection, 

 which by rain or surface washings may readily gain access to a 

 water supply, and thus to milk or its utensils. 



Summapy. — We may now briefly epitomise the meaning of the 

 above facts and their relation to typhoid fever epidemics arising 

 from milk pollution. We have seen that the disease is commonly 

 spread by polluted excreta, in its early stages by alvine discharges, 

 in its later stages and during convalescence, in a certain number 

 of cases, by the urine ; that the bacillus may remain in the 

 body for long periods after convalescence, and hence apparently 

 healthy persons may carry about and possibly disseminate 

 the seeds of the disease for months or even years ; that the 

 bacillus may be voided in countless numbers during such 

 periods ; that under certain circumstances such discharges, or the 

 dried dust resulting ultimately therefrom, may contaminate water 

 or milk ; that when this accident occurs, a comparatively small 

 pollution may lead to a wide-spread epidemic among persons con- 

 suming such water or milk ; and finally, that there is some evidence 

 to suppose that the virus of the disease may remain dormant but 

 alive for long periods of time in a saprophytic stage of existence. 

 But little reflection will be necessary to convince any careful 

 observer that an intelligent appreciation of these facts is of 

 essential importance in considering the relationship of polluted 

 milk to typhoid fever, or as, in part, explanatory of spasmodic or 

 apparently spontaneous or repeated outbreaks. 



The Bacillus of Typhoid Fever 



Turning now to consider some of the more important points in 

 relation to milk-borne epidemics of typhoid fever, we are met at the 

 outset by the as yet unproved specificity of Eberth's B. typhosus. 

 This organism has not fulfilled Koch's postulates, is not always 



* Brit. Med. Jour., 1902, vol. ii., p. 941. 



