THE RELATION OF LIFE TO OTHER FORCES. 309 



ture is necessary for the beginning of life, is partly expended as chemical 

 power, which causes certain modifications in the nutrient material sur- 

 rounding the embryo, e.g., the transformation of starch into sugar in the 

 act of germination; partly, it is transformed by the germ itself into 

 vital force, whereby the germ is enabled to take up the nutrient material 

 presented to it, and arrange it in forms characteristic of life. Thus the 

 force is expended, and thus life begins when a particle of organized 

 matter, which has itself been produced by the agency of life, begins to 

 transform external force into vital force, or, in other words, into a 

 power by which it is enabled to grow and develop. This is the true 

 beginning of life. The time of birth is but a particular period in the 

 process of development, at which the germ, having arrived at a fit state 

 for a more independent existence, steps forth into the outer world. 



The term "'dormant vitality," must be taken to mean simply the exist- 

 ence of organized matter with the capacity of transforming heat or other 

 force into vital or growing power, when this force is applied to it under 

 proper conditions. 



The state of dormant vitality is like that of an empty voltaic battery, 

 or a steam-engine in which the fuel is not yet lighted. In the former 

 case no electric current passes, because no chemical action is going on. 

 There is no transformation into electric force, because there is no chem- 

 ical force to be transformed. Yet, we do not say, in this instance, that 

 there is a store of electricity laid up in a dormant state in the battery; 

 neither do we say that a store of motion is laid up in the steam-engine. 

 And there is as little reason for saying there is a store of "vitality in a 

 dormant seed or ovum. 



Next to the beginning of life, we have to consider how far its continu- 

 ance by growth and development is dependent on external force, and to 

 what extent correlated with it. 



Mere growth is not a special peculiarity of living beings. A crystal, if 

 placed in a proper solution, will increase in size and preserve its own charac- 

 teristic outline; and even if it be injured; the flaw can be in part or wholly 

 repaired. The manner of its growth, however, is very different from that 

 of a living being, and the process as it occurs in the latter will be made 

 more evident by a comparison of the two cases. The increase of a crystal 

 takes place simply by the laying of. material on the surface only, and is 

 unaccompanied by any interstitial change. This is, however, but an 

 accidental difference. A much greater one is to be found in the fact 

 that with the growth of a crystal there is no decay at the same time, and 

 proceeding with it side by side. Since there is no life there is no need 

 of death the one being a condition consequent on the other. During 

 the whole life of a living being, on the other hand, there is unceasing 

 change. At different periods of existence the relation between waste and 

 repair is of course different. In early life the addition is greater than 



