Tivo Kinds of Life-Processes 39 



mous expression of the chemical properties which the 

 carbon-atom has at the temperature of our earth." 



Furthermore if we take into consideration the num- 

 berless isomers, which especially the more complicated 

 compounds of carbon, such as protein bodies, can form, 

 according to the present chemical theories, there can 

 hardly be any doubt that we shall some day succeed in re- 

 ducing the hereditary characters of all organisms to chem- 

 ical differences of their protoplasmic basis. 4 



But, much as such general considerations may help to 

 further our need for a uniform conception of all nature, 

 they are still far from serving us, especially at the present 

 time, as a basis for a theory of heredity. 



Experimental physiology of plants and animals has 

 succeeded in reducing many of the processes of life to the 

 chemical effects of the involved compounds, to repeat 

 them in part outside of the organism, but in part also to 

 demonstrate the fact that their behavior in the living body 

 is ruled by the general laws of chemistry. Into an 

 understanding of the processes of breathing, nutrition, 

 and metabolism we have been initiated in a simply as- 

 tonishing manner by numerous investigators, and the 

 purely mechanical manifestations of energy which ac- 

 company growth and motion have also, in great part, 

 been analyzed and reduced to general laws. But the chief 

 discovery of these studies is that two kinds of processes 

 occur in the living body. In the first place, those that are 

 separable from living substance, and can therefore be ar- 

 tificially imitated, or even exactly duplicated. In the 

 second place, those that are inseparable from that sub- 

 stratum, and which indeed find their existence in the 



4 Cf. Haeckel, E. Generelle Morphohgie. 1: 277, and Sagiura, 

 Shigetake. Nature 27: 103. 1882. 



