THE ORDERS OF CELL ACTIVITIES 241 



these continue. All cell activities are at bottom chemical or 

 physical changes in the relationships of the cell molecules and 

 their constituents, and so living matter is similar to matter of 

 all other orders in that molecular changes and activities require 

 to be set in motion by the influence of forces acting from without. 



To this broad statement it may be objected that the remark- 

 able investigations of late years upon radium and allied bodies, 

 notably those of Rutherford and other pupils of Sir J. J. Thomson, 

 have demonstrated that every individual atom of matter exhibits 

 an inherent activity of its constituent electrons, and, therefore, 

 energy from without is not an essential pre-requisite ; that in its 

 very essence matter is a storehouse of energy, and that thus 

 even inert non-living matter possesses the potentiality of auto- 

 matic activity. Here, truly, we plunge into very deep waters. 

 To such objections I would reply that the studies upon radium 

 so far only exhibit the possibility of these inherent atomic activi- 

 ties leading to the dissociation of electrons and coincident libera- 

 tion of energy, whereas the striking feature of living matter 

 is characteristically its capacity to associate, to build up from 

 its surroundings, other matter like unto itself. Nevertheless 

 my colleague, Professor Barnes, who, as a co-worker with Ruther- 

 ford at the time when he was making his remarkable discoveries, 

 speaks with high authority, assures me that the activity of 

 the electrons, so far as we can determine with our present know- 

 ledge, is wholly uninfluenced by, and presumably, therefore, 

 not initiated by, influences acting upon the atoms from without. 

 Up to the present, the greatest heat and the greatest cold to 

 which radium has been subjected have not been found to influence 

 in the slightest the rate of emanation of the radium rays. In 

 other words, the rate of motion of the electrons is unaltered by 

 extreme temperature changes. It may, therefore, be that in 

 this automatic activity of the atom we have the primal basis 

 of the automatic activities which here I am discussing ; that, 

 just as there are inherent attractions and repulsions within 

 the atom, so there are inherent attractions and repulsions of 

 the molecules that constitute the cell. 



If this be the case, how are we to picture the development 

 of automatic activities ? In this way, namely, that the cell is 

 not a single substance, but a complex of many, with central 

 nuclear matter, and a cytoplasm of proteid matter which presents 



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