HABIT AND NEOPLASIA 249 



But doing this, obviously, they sacrifice their function as 

 epidermal cells. Cells growing down into underlying tissues 

 cannot function as an epithelium. And thus, coincidently, in 

 these cells we have the vegetative powers exalted and the func- 

 tional activity depressed. Now, while there is a certain mean 

 or level at which moderate function, by stimulating increased 

 assimilation, may stimulate increased cell growth, it must be 

 recognized that growth and function are diametrically opposed 

 states of cell activity. Growth demands that matter taken as food 

 is built up into the cell substance and becomes associated, with 

 coincident storage of energy ; function, on the contrary, demands 

 dissociation, with liberation of energy. And, as a matter of 

 fact, your actively functioning cell shows no signs of proliferating. 

 Your actively vegetative cell is of embryonic type, i.e. shows 

 little signs of differentiation, and therefore of functional capacity. 

 We observe, thus, that these down-growing epithelial cells — 

 and the same is true of all early malignant growths — present 

 coincidently depression of function and exaltation of vegetative 

 power. And I would lay down that it is this modification of the 

 cell activities that is the basis of neoplasia ; that what is charac- 

 teristic of the true tumour is that the component cells, from 

 one or other cause — displacement, irritation and so on, — have 

 lost the habit of function, and coincidently, as the nutritive 

 material taken in needs to be used up, the very accumulation 

 of the newly formed cell substance, disturbing, as it does, the 

 surface-to-mass relationships of the cell, becomes in itself the 

 stimulus to cell division, in order that the due relationships may 

 be restored. Thus is developed the habit of growth, replacing 

 the habit of function, and it is, I hold, this habit of growth that 

 characterizes all true tumours. It is at least suggestive that 

 the one non-surgical method of treating malignant growths 

 that is giving definite results at the present moment, when 

 appropriately applied, essentially depends upon a specific reduc- 

 tion in the growing power of the tumour cells. It is now well 

 established that radium and X-rays act especially upon the 

 vegetative cells of the organism, and, characteristically, it is 

 the actively vegetative malignant tumours, rather than the 

 benign with their more highly differentiated cell elements, that 

 are arrested and undergo absorption after treatment with either 

 radium or X-rays. 



