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7 
GROWTH AS A FUNCTION OF CELLS. By CHARLES SEDGWICK 
MINOT. 
The phenomena of growth in all metazoic animals must be re- 
garded as functions of the cells, derived from the primitive egs- 
cell_—_ the impregnated ovum. ‘The discussion of growth from this 
stand-point has not, as far as I am aware, been hitherto attempted. 
In the following pages I offer for consideration the arguments and 
conclusions I have gathered as to the factors which determine 
growth. 
The measure of growth usually adopted is the weight of the body — 
but this does not determine necessarily the increase in the amount of 
living matter, because not only does the protoplasm of the cells in- 
crease, but also the intercellular substances, the non-living matters 
enclosed in the protoplasm, and the water with which the albumen- 
oids are imbibed. Evidently unless the proportion remains the same 
between the vitalized and the dead substances the weight of the body 
does not indicate with exactitude the amount of the living matter — 
yet this would certainly be the most satisfactory measure of growth. 
If, on the other hand, we regard the individual cell as the structural 
unit and do not lay much stress upon the distinction usually drawn 
between the protoplasm and the deutoplasm, it would be sufficient to 
determine the number of cells at successive periods. At present at 
least we have no means of actually counting the cells of the body. 
Nor can we calculate the number of cells by dividing the total 
volume of the body, which could be readily measured, by the volume 
of a single cell, because the cells united in one body are of various 
sizes. ‘This difficulty could be surmounted if we knew the average 
