770 MODE OF SPREAD OF INFECTIVE DISEASES. 



Prophylaxis 

 by influencii 

 the individu 

 predisposi- 

 tion. 



Prophylaxis 

 by destruction 

 or removal of 

 the infective 

 agents. 



General pro- 

 phylactic 

 measures. 



7. The most Important Prophylactic Measures against 

 the Spread of the Infective Diseases. 



We can very easily deduce the prophylactic measures 

 against infective diseases from the facts as to the mode 

 of spread of these diseases which have been referred to 

 in the foregoing paragraphs. 



In some cases it seems hest to direct our precautionary 

 [ methods rather towards the individual predisposition of 

 the body than towards 'the infective agents, and in fact 

 to neglect the latter more or less completely. The most 

 marked example of this is tuberculosis (see p. 752). 

 It is possible also that other infective diseases will be 

 best held in check by such a method of prophylaxis, and 

 probably there is a great field for investigation and for 

 practical work in this direction. 



Among the means of lessening the individual pre- 

 disposition we have also protective vaccination, the 

 practical value of which with the single exception of 

 vaccination for small-pox must, however, for the 

 reasons given above (p. 760), be judged on the whole 

 unfavourably. 



In the great majority of cases, however, our prophy- 

 lactic measures deal with the infective agents themselves, 

 and seek to destroy them, or to hinder their development 

 or spread. 



The reporting of cases, quarantine, and the isolation 

 of the sick are precautions which do not require any 

 special discussion, nor do the points which would have 

 to be discussed in connection with them specially con- 

 cern the matter of this work, and we may therefore pass 

 them over. We have here to do with the measures for 

 the destruction and removal of the sources of infection 

 mentioned on p. 736, and for interfering with the modes 

 of transport (see p. 739). The following are the most 

 important precautions in this direction : 



a. Measures which are generally applicable. In cases 

 of disease it is of the first importance to destroy or disin- 

 fect all the excreta of the sick which may contain the effec- 

 tive ugcnts, and all the objects contaminated with them, 



