THE CAUSATION OF DISEASE. 347 



numerary fingers ; there is no hard distinction between these 

 and hereditary fatty, glandular, cartilaginous, or osseous growths ; 

 these again cannot be separated from definite tumours of 

 similar structure ; finally, there is no abrupt step from 

 innocent tumours to recurrent fibroids from which true cancer 

 may be evolved. Now, I do not allude to this particular view 

 in order to subvert it ; for Paget is most careful to impress 

 upon his readers that the above may not be the exact mode of 

 evolution, and that he merely ' ' hazards a guess " ; I men- 

 tion it only because it shows that when he wrote the lecture 

 his mind was dwelling upon the S — that he was thinking of 

 cancer as evolving through S, and this indeed is one possible 

 origin of malignant disease. 



The growth of a malignant tumour is most remarkable. 

 A tissue which, it may be, for many years has been living 

 healthily, suddenly and sharply diverges from its wonted mode 

 of growth. The change is not a mere hypertrophy or atrophy, 

 nor is it simple degeneration, any one of which may be brought 

 about by the body through its own power of modifying cell-E 

 — of increasing or decreasing blood-supply or of modifying 

 nerve influence. The process is quite peculiar, for, while 

 the nutritive activity of the part is actually increased, and 

 sometimes enormously so, the change is a retrogressive one, 

 the tumour-tissue, taken as a whole, being not only quite 

 different from that of the surrounding parts, but also of inferior 

 value from an evolutionary point of view. Now, bearing in mind 

 that every cell in the body is a separate organism, surrounded 

 by its own special E, this peculiar behaviour on the part of a 

 tissue which for years has been calmly and peacefully carrying 

 on its proper functions, is strongly suggestive of a sudden and 

 peculiar modification of its cell-E. In a meadow we sometimes 

 observe dark patches of grass growing more luxuriantly than 

 the rest, and, on seeking for the cause, we find that it is due 

 to altered E, in the shape of a different soil ; similarly, if in 

 the body we observe one patch of tissue taking on luxuriant and 

 abnormal growth, a modification of E is strongly suggested. 



But, even though the abnormal growth be due to a peculiar 

 cell-E, this might conceivably be independent of any peculiar 

 external E ; it might, namely, be wrought by the body itself 



