SUMMARY. 45 



in this inquiry by omitting all consideration of the 

 subjective conditions, and considering only the ob- 

 jective facts. In animals the subjective condition 

 is but a very crude inference from the objective 

 facts. 



Summary. The term " expression," as used in this 

 work, does not imply that the subject of which it is 

 connoted has the property life. Nutrition is said 

 to occur only in living beings. We do not know 

 much about the vital process nutrition, but we can 

 observe and study its results, or objective signs. 

 The outcome of nutrition affords the best examples 

 of direct expression. The principal results or ex- 

 pressions of nutrition are growth, or trophic 

 action; movement, or kinetic action; evolution, 

 and retentiveness. 



Growth concerns the material structure of the 

 subject the kind of action which produces a change 

 in the structure of the subject; it is, therefore, called 

 a "trophic action," in contradistinction to that 

 result of nutrition which only produces movement, 

 and is called in this work " kinetic action." 



Permanent impressionability, or retentiveness in 

 a living structure, may be expressed by a reflex 

 action ; it is not a process of evolution, but gives a 

 tendency to resist change. 



Movement is an outcome of changes occurring in 

 a living subject; this is a deduction from the law of 

 conservation of energy. 



Development is expressed in various modes by 

 the ratio of growth, weight, and proportions (trophic 

 action), or by series of movements and reflex actions 



