6 ELEMENTS OF BIOLOGY 



that activates living objects? There are two possible ways o£ con- 

 ceiving of the powers that give living bodies their peculiar prop- 

 erties. Either these forces that show themselves as irritability, 

 growth, reproduction, and so on, represent transformations of energy 

 according to laws we are familiar with in the non-living world, or 

 else a supernatural force outside our ability to measure is the 

 activating factor in life. The first of these concepts is termed mech- 

 anism; the second, vitalism. 



If we adopt the view that life is a manifestation of some super- 

 natural force, vitalism, then any attempt to understand such a force 

 is futile, for it could not be recognized by our senses. It could not 

 be weighed, measured, nor controlled, for such an activating prin- 

 ciple is not subject to the laws of energy, nor to any other known 

 laws of Physics or Chemistry. The biologist adopts the view as a 

 working hypothesis or supposition, that the vital activities, irrita- 

 bility, contractility, reproduction, and so on, are visible evidence of 

 the operation in protoplasm of the laws of Physics and Chemistry 

 that apply everywhere else in the Universe, that the manner in 

 which these laws operate in the living body is knowable, although 

 in many cases indeed not yet known. This point of view is justified 

 by the fact that, with mechanism as a working theory or basis, 

 very much has been discovered concerning the nature of life. Each 

 decade marks progress in enlarging our understanding of how 

 protoplasm operates in carrying on the activities that are peculiar 

 to it. Here we shall regard the characters of living objects as mani- 

 festations of the laws of Physics and Chemistry operating in a pe- 

 culiar substance, protoplasm. 



Nature of Matter. Elements: Life, then, from this point of 

 view, consists of a complex of phenomena, each of which is an ex- 

 pression or manifestation of energy, in a body composed of finite 

 materials. To appreciate its nature it is necessary first to compre- 

 hend the fundamental concepts of the nature of matter and of the 

 laws of energy, for life is one of the consequences of matter and 



