IN LIVING MATTER 9 



such a view tenable. Nor is the chemical composition of the 

 complete animal represented in that of the early embryo. It is 

 evident that the course of cell-division and development by which 

 a constant species is arrived at are not attained by means of 

 structure in the embryo, the ingress of chemical energy from 

 without, and the action of diffusion and osmosis. But if there be 

 added to these the presence of a distinct type of energy peculiar to 

 living matter which controls and regulates the energy phenomena 

 of the growing embryo, and which is attuned initially to the species 

 of living creature to which the embryo belongs, then a more feasible 

 basis for the explanation of the course of development of the indi- 

 vidual becomes apparent. At each step, this biotic energy will 

 regulate the growth and division of the cells of the growing embryo. 

 As each stage is reached, similar changes in the distribution of 

 biotic energy will occur as in previous generations, for the embryo 

 will arrive at them, with the same distribution as in past genera- 

 tions of its store of energy, and hence the same phases in the 

 energy phenomena will repeat themselves, except in so far as 

 these are modified by nutrition and environment in a secondary 

 degree. 



In the process of growth, the oxidation of the food yields the 

 necessary energy, which is converted into biotic energy, and then 

 this is utilised in building up fresh cellular material, in fabricating 

 chemical substances for the use of the cells and in producing other 

 forms of energy. Throughout, the biotic energy retains certain 

 intrinsic characteristics derived from the fertilised ovum, and by 

 the impress given by these the process is directed. 



IV. The fundamental properties possessed by living matter of 

 irritability, contractility, and conductivity, are all energy phenomena 

 characteristic of life, and nowhere manifested by the operation of 

 other forms of energy in non-living matter. While it is un- 

 doubtedly true that the exhibition of these properties in living 

 tissue are accompanied by manifestations of other forms of energy, 

 such as chemical change, electricity and heat, and indeed neces- 

 sarily must be, since the cell obtains the energy used in the pro- 

 duction and propagation of these changes from such non-biotic 

 forms of energy, yet the alterations in irritability are characterised 

 by phenomena which are not chemical, electrical, or caloric, and 

 cannot be placed under any of the known forms of non-biotic 

 energy. 



