94 THE STORY OF LITE'S MECHANISM. 



and nitrogen, and closely related to ordinary pro- 

 teids. This substance was the basis of living activ- 

 ity, and to its modification under different condi- 

 tions were due the miscellaneous phenomena of life. 



(c) Significance of Protoplasm. The philosophi- 

 cal significance of this conception was very 

 far-reaching. The problem of life was so sim- 

 plified by substituting the simple protoplasm for 

 the complex organism that its solution seemed 

 to be not very difficult. This idea of a chemical 

 compound as the basis of all living phenomena 

 gave rise in a short time to a chemical theory of 

 life which was at least tenable, and which ac- 

 counted for the fundamental properties of life. 

 That theory, the chemical theory of life, may be 

 outlined somewhat as follows : 



The study of the chemical nature of substances 

 derived from living organisms has developed 

 into what has been called organic chemistry. 

 Organic chemistry has shown that it is possible 

 to manufacture artificially many of the compounds 

 which are called organic, and which had been 

 hitherto regarded as produced only by living 

 organisms. At the beginning of the century, it 

 was supposed to be impossible to manufacture 

 by artificial means any of the compounds which 

 animals and plants produce as the result of their 

 life. But chemists were not long in showing 

 that this position is untenable. Many of the 

 organic products were soon shown capable of 

 production by artificial means in the chemist's 

 laboratory. These organic compounds form a 

 series beginning with such simple bodies as 

 carbonic acid (C0 2 ), water (H 2 0), and ammonia 



