532 PROTOPLASM 



If we group all substances that are on or near the border line 

 between the living and the nonliving, we obtain a series similar 

 to the one given by A. E. Boycott; there are first the simple 

 proteins, then the nonliving enzymes which cannot multiply, 

 then "enzymes" (like lysozyme) which can multiply in the 

 presence of bacteria, then nonpathogenic viruses of the type of 

 bacteriophage, pathogenic viruses, filterable bacteria, and finally 

 visible bacteria. In such a series, it is impossible to say where 

 life begins and where it ends. 



Vitalism and Mechanism. — ^The constituents of protoplasm, 

 which are the material basis of life, may serve merely as the 

 medium in which certain vital forces play. The possible existence 

 of a vital force apart from those earthly ones that control all 

 other natural phenomena has long been entertained and has given 

 rise to the philosophy known as vitalism (or historism) in contrast 

 to mechanism. Early religious tendencies led scientists to the 

 belief that plants and animals differed from nonliving matter 

 in that they were controlled or operated by a spiritus vitae, or, 

 as the Germans call it, a Lebenskraft. Such a vital force is the 

 basis of the philosophy known as vitalism. 



There are two points of view in regard to vital force; one 

 {e.g., that of Driesch) holds it to be distinctly not of this world 

 (entelechy is "neither a kind of energy nor dependent on any 

 chemical material"), and the other (e.g., that of Rignano) holds 

 it to be of this world and therefore to be classed with other forms 

 of energy only different from them — of the same family but a 

 new species, so to speak ("life is a form of energy suis generis"). 

 The former point of view has the virtue of being definite and 

 beyond reach, but the latter, in attempting to harmonize vital 

 force with known forms of energy, falls into an error. All 

 energy is additive; chemical energy can be added to electrical, 

 and electrical to radiant, etc.; that is to say, the total energy 

 of a system is the sum of the separate energies (E = IiEi). As 

 vital energy cannot be added to other forms, it is consequently 

 not energy as understood in physics. 



A vital force was presumed to give to plants and animals the 

 power to synthesize organic substances which could not, so it 

 was supposed, be artificially produced in the laboratory. Organic 

 chemistry was so called because it was thought that the carbon 

 compounds with which this branch of science deals were made 



