296 ON GROWTH AND OVERGROWTH 



the condition of uncontrolled proliferation ? It is clear that 

 at first at least that same stimulus which had led to increased 

 assimilation in the parent cells must continue in evidence, for, 

 if this were not so, then the new cells would either lead but a 

 latent existence, or the tissue in which they are present reverting 

 to a normal state, these cells would gain the same relationships 

 as were possessed previously by their parent and " sister " cells ; 

 they would develop into normal functional cells with specialized 

 structure. We are bound, therefore, to assume that this is not 

 the case that the primary stimulus continues to act for a certain 

 period, and that as a result of this continued action there is 

 developed a colony of cells all tending actively to proliferate. 

 But now the greater the proliferation the more inevitable must 

 it be that a certain number of new cells assume relationships 

 more and more removed from those proper to the parent cells. 

 Some of these new cells, at least, must pass to a greater distance 

 from the blood capillaries and blood supply, from the lymph 

 channels and the terminal nerve supplying the part, and becoming 

 thus still further removed from the ordinary relationships of 

 the cell forming the particular tissue which has given them birth, 

 still less are they capable of performing normal functions ; still 

 more, granted adequate nutrition, are they liable to proliferate. 

 If becoming thus heterotopic their nourishment is cut off, they 

 of necessity die or at least their continued proliferation is arrested. 

 If also the very abundance of the new cells formed leads to 

 marked increase of the pressures acting upon those cells, growth 

 is equally arrested. 



According, therefore, to (a) the time of continuance of the 

 primary stimulus (under which term, be it remembered, for the 

 time being I here include everything capable of inducing modified 

 cell relationships to an extent sufficient to permit continued 

 anabolism with perverted katabolism) ; according also to (6) 

 the relationship assumed by these new cells one to the other ; 

 and (c) the tensions to which they are subjected, so do we 

 have or not have the conditions favourable for continued and 

 increasing growth and development of new cells. It is this 

 continuance of the primary stimulus coupled with continued pro- 

 liferation which gives us the second stage in the evolution of the 

 tumour. These newly proliferated cells may exhibit various 

 departures from the structure and appearance of the fully formed 



