x.] DISEASE. 181 



rooms. The explanation of the fact that we have 

 been discussing appears therefore to be summed up in 

 the sinole word — Infection. 



Consumptivity. — Before abandoning the topic of 

 hereditary consumption, it may be well to discuss it 

 from the same point of view that was taken when 

 discussing the artistic temperament. Consumption 

 being so common in this country that fully one person 

 out of every six or seven die of it, and all forms of 

 hereditary disease being intermixed through marriage, 

 it follows that the whole population must be more or 

 less tainted with consumption. That a condition which 

 we may call " consumptivity," for want of a better 

 word, may exist without showing any outward sign, 

 is proved by the fact that as sanitary conditions worsen 

 by ever so little, more persons are affected by the 

 disease. It seems a fair view to take, that when the 

 amount of consumptivity reaches a certain level, the 

 symptoms of consumption declare themselves ; that 

 when it approaches but falls a little short of that level, 

 there are threatening symptoms ; that when it falls 

 far below the level, there is a fallacious appearance of 

 perfect freedom from consumptivity. We may reason- 

 ably proceed on the hypothesis that consumptivity 

 might somehow be measured, and that if its measure- 

 ment was made in each of any large group of persons, 

 the measures would be distributed " normally." 



So far we are on fairly safe ground, but now un- 

 certainties begin upon which my data fail to throw 



