OF DISEASE GERMS. 



of its presence being determined by the state of the 

 system and the conditions to which it is exposed. So 

 that of two persons equally infected, but living under 

 very different, and, in some respects, opposite con- 

 ditions, the germs in one, after remaining dormant for 

 a long while, may at length die and become extinct, 

 while in the other organism, being placed under con- 

 ditions favourable to their activity, the germs grow and 

 multiply, and perhaps even destroy the body, it may 

 be at a very early age. And it is possible that in one 

 organism more than one kind of morbid bioplasm may 

 be dormant, the conditions favourable to the growth 

 of one being unfavourable to that of another. So that 

 of many kinds present, one or more may become 

 active'. The careful consideration of facts of observa- 

 tion in connection with the subject of contagious 

 diseases, leads to the conclusion that in all cases where 

 disease is developed two things are necessary I, the 

 presence of the living disease germ ; 2, the external 

 conditions favourable to its growth and multiplication. 

 It seems to me, therefore, that if every disease germ 

 were destroyed to-morrow, the result would probably 

 be far less favourable to humanity than if every 

 organism could be placed under the conditions most 

 favourable for resisting attack, and therefore under 

 circumstances which would interfere with .the growth 

 of the disease germ, which at length would die. And 

 for this reason that in the latter case the extinction 

 of disease germs, although more gradual, would not 



