BEKGSON S PHILOSOPHY OF THE ORGANISM. 17 



sensory-motor system. Now these distinctions are not 

 absolute ones any more than are the morphological 

 distinctions between plants and animals. The zoospores 

 of the Algae possess at least the rudiments of a sensory- 

 motor system and are highly motile, and purposeful 

 movements may be carried out by the higher plants. On 

 the other hand, synthetic processes occur in the animals, 

 and these, as in cases of parasitism, may exhibit torpor 

 and immobility. Further, in the cases of symbiotic 

 relationships of plant and animal, we see what might be 

 regarded as indications of a primitive coalescence of both 

 sets of tendencies, or at least we see the possibility of 

 their co-existence in the same organism. 



The general characteristics of life as we know it are 

 therefore (1) the slow accumulation of energy by the 

 transformation of compounds of low chemical potential 

 into others of high chemical potential; and (2) the 

 sudden transformation of these high potential com- 

 pounds into low potential ones, and the regulation of the 

 mechanical energy thus liberated by a sensory-motor 

 system of mechanisms. 



If we have to give a definition of life it must be one 

 employing these facts of experience. Now we see at 

 once that here we have something in the nature of a 

 mechanism, but it is a mechanism which is difficult to 

 describe in terms of the concepts of thermodynamics. 

 Let us try to think of life in this way : — the metabolic 

 processes of the organism in general, that is, its energy 

 transformations, are represented by two phases (1) com- 

 pounds of low potential — carbon dioxide, water and 

 nitrate are built up into compounds of high potential — 

 carbohydrate, oils and proteid, and work is done on the 

 organism, the requisite energy being absorbed from the 

 ether in the form of solar radiation. This is the plant 



