PRESIDENTIAL ADDRESS. 85 
or its deposits, or by the pressure effects of the tumour 
masses. 
What is the essential basis of the malignant process? Is 
it due to changes inherent in the cells or the tissues, or to 
a reaction to parasites of external origin? Is the process 
intrinsic or extrinsic? If the latter, we must seek to ex- 
clude the causal factor or factors; if the former, to ascer- 
tain and control the means by which the departure from 
normal is brought about. 
The great body of cancer investigators hold the view, 
based on a reasonable assessment of all the known data, 
that an external parasite—protozoal or otherwise—is not 
an essential in. the development of true malignant neo- 
plasms. It is true that reactions of the body cells to foreign 
parasites, some bacterial, some animal, may ape in vari- 
ous ways malignant neoplasms, and that such parasites may 
aid in the starting of a cancer. But the balance of evidence 
is strongly against the view that such foreign living bodies 
are the essential cause, though this view cannot be con- 
sidered as conclusively discounted. 
To my mind, the nature of cancer is intimately bound 
up with the development of the body cells. I believe it 
to be the expression, by nearly effete somatic cells, of an 
attempt by them to prevent extinction by the formation of 
gametoid tissue—that, in fact, they are trying to form 
gametes or sex cells with the object of these uniting to form 
individuals of a new and rejuvenated generation. That 
under the circumstances they lamentably fail is only to be 
expected from their prentice hands. Their gametoid tissue, 
though bearing some of the marks of normal gametogenic 
tissue, is produced in a bed unprepared for it, and in sur- 
roundings not in keeping with its needs. The gametes 
formed are clumsy, unwieldy cells, and not the perfect 
mechanical and physiological units represented by the 
spermatozoa and ova of normal development. 
