

MY WORK AND BACTERIOLOGY 311 
systemic infection, hard to be believed; and ulti- 
mately requires agencies for waking the tubercle 
Bacilli into activity, just such as I suppose may be 
adequate for calling them into being—namely, mal- 
nutrition and conditions of lowered vitality, howso- 
ever produced: though among such factors impure 
air and inadequate or improper food must take an 
important place.” 
But in accordance with the view favoured by me, 
as to the frequent origin of the tubercle Bacillus by 
transformation of common Bacilli constantly gaining 
access to the body, we might return to something 
more like the doctrine “that prevailed concerning 
the etiology of phthisis only a few years ago, when 
the affection was freely recognised as generable 
in the individual, altogether apart from contagion, 
and contagion was supposed to take only a limited 
share in the production of the disease. This seems 
the more rational and most warranted view to take. 
It is one which would tend to lay stress upon the 
need for prevention as well as cure, but it would not 
encourage the view that the disease could be exter- 
minated, or even very largely diminished, by the 
provision of ‘sanatoriums’ and by efforts to minimise 
the risk of contagion [—all important as these un- 
doubtedly are]. I merely mean to imply that, 
in my opinion, contagion is as much over-rated as 
genesis is under-rated, and that our notions concern- 
ing prevention must not be too much centred upon 
the mere elimination of contagion.” As Professor 
Hueppe says, ‘the resisting power of a population 
can change according to the social conditions. If 
