APPENDIX E. cxiii 



There are so-called ' specific growths/ just as there are 

 ' specific diseases' of a more general or constitutional charac- 

 ter. The life-history of such growths as cancer and tubercle 

 is a subject of great intrinsic interest; though the import- 

 ance of their study is much enhanced by the fact, which I 

 shall strive to make plain, that their modes of origin and 

 distribution within the body are capable of throwing much 

 light upon the origin and distribution of epidemic and spe- 

 cific infectious diseases amongst the community. 



The term ' specific/ as applied to diseases, is confusing, 

 and apt to carry with it a crowd of erroneous notions. Doc- 

 trines of 'specificity' have, however, been fashionable in 

 medicine, though they are now growing more and more into 

 disrepute. Thirty or forty years ago, amidst all the jargon 

 concerning homoplastic and heteroplastic, euplastic and caco- 

 plastic growths, would it not have been deemed rank heresy 

 to profess a disbelief in the prevalent notions concerning the 

 unalterable and ' specific ' nature of cancer and of tubercle ? 

 Here were products altogether peculiar, and not derivable, 

 as it was thought, from the normal tissues of the body- 

 having laws of growth and distribution peculiar to themselves, 

 and an origin which was shrouded in the mystery of a remote 

 past. In view of this doctrine as to the specific and alien 

 nature of the products, how natural was it that an undue 

 stress should have been laid upon the fact that a tendency to 

 the occurrence of such modes of growth may be hereditarily 

 transmitted ; how easily explicable is the facile and popular 

 resort to the notion that, where multiple cancerous growths 

 exist, the primary new formation has given rise to a seedling 

 progeny by means of actual cancer ' germs.' Slowly but 

 steadily these views have been undergoing a progressive 

 modification. The anatomical elements of cancer and tu- 

 bercle are now known to have no special and peculiar charac- 

 teristics, and they are believed to be as easily derivable 'from 



VOL. it. h 



