278 ON GROWTH AND OVERGROWTH 



seen to be especially affected, certain villages, and even certain 

 houses in those villages — and this apart from blood relationship 

 between the affected individuals. The incidence is, if I may 

 so express it, of a miasmatic type, resembling, for example, 

 that of malaria. 



3. That the lesions produced by the growth of malignant 

 tumours within the organism are comparable with those induced 

 by certain known infective agencies, and that a close analogy 

 can be drawn between the tubercle and the dissemination of 

 tuberculosis, and the primary cancer nodule and the metastatic 

 cancerous or sarcomatous growths. Just as in chronic affections 

 there are, as a rule, single primary foci of origin, so with the 

 malignant neoplasms ; and just as there is extension of the 

 tuberculous process by continuity (with the destruction of the 

 surrounding tissues and their replacement by new tissue), by 

 the lymphatics, or by the blood stream, so it is in connexion 

 with neoplasms and their progressive development in the 

 organism. 



4. That the more carefully material from malignant tumours 

 is examined, the larger is the proportion of cases in which certain 

 intracellular and extracellular bodies are to be recognized. The 

 series of forms seen, while large, is, according to each individual 

 observer, remarkably constant, and not to be regarded as in- 

 dicative of cell-degeneration, though observers differ between 

 themselves as to the specific series of forms. It is generally 

 agreed that these bodies are most numerous in the young growing 

 edge of the tumours rather than in the older central cells in 

 which degeneration might be expected to show itself. While 

 but a few years ago the observations of Sjobring, Ruffer, Metch- 

 nikoff, and others led to these bodies being regarded as parasitic 

 sporozoa, and so as being of animal nature, among upholders 

 of the parasitic theory the trend of opinion at the present time, 

 following Russell, Roncali, and Sanfelice, is to regard them as 

 of vegetable origin, as blastomycetes or yeast-like growths. 

 But within the last few weeks there have been indications that 

 the sporozoon theory is of late being actively supported. 1 



1 [In the years that have elapsed since this address was delivered, as one 

 after another other species of pathogenic microbes have been recognized, with 

 a striking inevitability, one after another these have been announced as the 

 causative agents of cancer-spirochaetes, amoebae, gregarines, chlamydozoa 

 and filterable or ultra-microscopic viruses.] 



