VITALITY 163 



man has passed the climax of his age, is so enormous 

 that the possibility of fallacy due to "the error of 

 random sampling" is reduced almost to zero. It is a 

 salient feature of the disease which cannot be disputed, 

 and we may regard is as an axiom that cancer attacks 

 people when they are trending downwards from their 

 physiological prime. The question is, therefore, What 

 happens in the tissues during this senescence which 

 renders them liable to the onset of cancer ? At the 

 time when these researches were first applied to the 

 investigation of cancer, this question could only be 

 answered in a speculative manner; but it was appre- 

 ciated that the conditions present after the prime of 

 life which predisposed to the disease might merely 

 depend on something in the nature of the oversetting 

 of a physiological balance. 



Vitality seems to be worthy of consideration as a 

 factor connected with the onset of malignancy. Very 

 old persons do not appear to be so liable to cancer 

 as those between the ages of 40 and 55 a circum- 

 stance which may possibly be due to a loss of vitality, 

 for it has already been mentioned that cancer is a 

 disease of the robust. Premature ageing, on the other 

 hand, seems to favour the onset of cancer; but in 

 conditions of decrepitude there is more freedom from it. 

 Tottering persons, such as are seen in asylums -and 

 institutions, do not so frequently develop carcinoma; 

 but people who are sufferers during their senescence 

 from the atrophic form of osteo-arthritis or from gout 

 are common victims. Let the reader visit a home for 

 incurables, and he w r ill there learn that many of the 



