TRANSMISSION OF FORCE. 165 



ability to more or less readily discern such changes as may 

 have occurred. 



Animals, by food, not only maintain the perfect structure 

 of the body, but also lay up in their tissues a store of power 

 for future needs. The power stored for the individual is 

 latent for a time, but reappears and becomes active when 

 required, in the resolution of once living structures, by the 

 vital processes. The force required for the purpose of the 

 germ is derived from the progenitor ; as the germ chauges its 

 condition it may derive force through its own development, 

 just as the body renews its force through its development. 

 When the force derived from the parent is insufficient for the 

 continuation of the development process to a self-supporting 

 condition, that is, to individual life, the germ must perish. 

 Consider how few germs of the millions ' contained in the 

 cow's ovary which can ever arrive at a stage when there is a 

 capacity for receiving fecundation. 



The primal force — or the force existing at the origin or first 

 recognition of any of our animals — need not be so inconceiv- 

 ably large. It is not requisite to suppose, with Prof. Huxley,* 

 that in the case of the successive viviparous broods of aphides, 

 a germ-force capable of organizing a mass of living structure 

 which would amount, as it has been calculated, in the tenth 

 brood to the bulk of five hundred million of stout men, must 

 have been shut up in the single individual, weighing possibly 

 one one-thousandth of a grain, from which the first brood was 

 evolved. The force transmitted is but that which has acted 

 on and influenced the transmitting cell, and this cell, under 

 unsuited conditions of development, perishes, and the force is 

 resolved into other forces; or, under suitable conditions, the 

 cell establishes a vitality independent of the parent, with the 

 possession of sufficient force to enable it to add to the forces 

 already possessed, in the way established by natural law. 

 To understand the germ-force of the case of the aphides under 

 consideration, we must couceive of the force transmitted to 

 be at least that sufficient for a single individual, and each 

 individual to elaborate through natural agencies a sufficient 

 power for its own growth and development and for transmissal 

 to its brood in turn. It but transfers a portion of that force 



* Organic Reproduction of Aphis, in Tenis. Trans. Vol. XXII., p. 215. 



