APPENDIX E. cxv 



cancer, as the results of experiments on the rodent animals 

 explain one of the modes of origin of tubercle. 



Is there anything specific in the mode of growth of these 

 products, and in their subsequent distribution within the body 

 of the affected person ? Just as an erysipelatous inflamma- 

 tion spreads by gradually inducing a similar morbid action 

 in adjacent parts, so does a cancer or a mass of tubercle 

 grow by a slower extension of the morbid modes of growth. 

 We have no more to do with a kind of implanted something, 

 increasing by a multiplicative reproduction, in the one case 

 than in the other. In both alike there are deviations from 

 the ordinary modes of growth, which gradually extend to 

 adjacent healthy parts. Neighbouring lymphatic glands be- 

 come affected in the case of tubercle and cancer-growths, 

 as well as where simple inflammations exist; and just as 

 the change in the gland in the case of inflammation must 

 be regarded as the result of a mere induced morbid action, 

 rather than as the product of the multiplicative reproduction 

 of a transmitted germ, so is a similar explanation open in 

 the case of cancer and tubercle. IModes of growth which 

 have been primarily induced may be also secondarily induced. 

 The kind of agency, which is at least probably potential 

 where the lymphatic system is concerned, or where particles 

 of morbid growths come into contact with serous ^ or mucous 

 surfaces, seems almost certainly operative when we come to 

 consider that wider distribution which is occasionally brought 

 about through the vascular system. The potency of the 

 ' exciting causes ' are here weakened, and new growths can- 

 not be initiated in distant parts or. organs by contact with 

 disseminated particles, unless the ' predisposing causes ' are 

 favourable and there is an ability in the part to take on the 

 morbid mode of growth. The action may be similar in kind 



^ See Dr. Sanderson's 'Report on the Communicability of Tubercle by 

 Inoculation' (' Eleventh Report of Med. Officer of the Privy Council'). 



h 2 



