254 BACILLI PATHOGENIC IN MAN. 



must always take place, that a condition of irritation, a 

 hyperaemia and detachment of epithelium, such as occurs, 

 for example, in animals after the injection of putrid 

 mixtures, prepares a spot for the entrance of the true 

 infective agents. 



If the view as to the important role played hy the 

 intestine in the production of infection is correct, it be- 

 comes probable that the transport of the typhoid bacilli 

 to the seat of infection occurs most frequently through 

 the food ; and very various articles of food are not less 

 suitable as vehicles than the drinking water which is 

 commonly blamed in a somewhat one-sided manner. 

 Transport by Articles of food and drinking water can evidently be 



articles of . . , .., , .... , , . -, , .. 



food. impregnated with large quantities of typhoid bacilli or 



spores in the most various ways; of great importance 

 for the continued existence and development of the 

 typhoid bacilli outside the body is, on the one hand, the 

 fact that many typhoid bacilli leave the body of the 

 patient in the form of resistent spores, and on the other 

 hand that their development can occur on the most 

 various nutrient materials at the ordinary temperature, 

 and that without any alteration of the nutrient material 

 noticeable to the naked eye. Thus the channels for the 

 spread of the infective material from the dejecta of 

 typhoid patients to articles of food are extremely nu- 

 merous, and are in a marked manner subject to chance, 

 which at one time follows no apparent rule, at another 

 time may present a deceptive appearance of law. It is 

 necessary to refer in illustration of this to the fact that 

 the dejecta containing spores are ultimately deposited on 

 garden earth, on fields, or on meadows, that the un- 

 altered spores may be thence transported to the dwellings 

 by fruit, man, &c., and by unforeseen actions and 

 accidents reach a suitable nutrient medium where they 

 can multiply plentifully, and from whence further 

 infection may eventually occur. 



It is necessary to bear in mind these numerous and 

 complex ways in which an infection may possibly occur 

 in order to some extent to meet the prevailing tendency 

 to treat these etiological questions in a schematic manner. 



