CHEMISTRY AND ITS DEVELOPMENT 221 



chemistry were established, and the atomic hypothesis had 

 lent to the science a keen power of penetration, it became 

 possible to approach the world of organic matter with the 

 hope of shedding some light upon its mystery. Since then 

 organic research occupied chemists almost exclusively dur- 

 ing a greater part of the nineteenth century, and the result 

 of that inquiry has been not only a vast store of empirical 

 knowledge of organic compounds, but also a set of general 

 principles that have strengthened the theoretical basis of 

 the science, and have led to some of the great industrial 

 achievements of modern times. 



Early in the nineteenth century it was universally be- 

 lieved that organic substances could not be produced with- 

 out the agency of the "force of life." Whether there is 

 such a distinct "force" and what its relations may be to 

 the measurable forms of energy, we do not. know as yet. 

 But we do know that organic compounds can also be pro- 

 duced by chemical agencies alone, without the intervention 

 of anything else. For chemists have actually succeeded in 

 building up from their elements many thousands of com- 

 pounds that occur ready formed only in the organisms of 

 animals and plants. The first of such compounds repro- 

 duced in the laboratory was urea, which Wohler made arti- 

 ficially in 1828. The old belief, however, lingered, some 

 chemists contending that urea could not be looked upon as 

 a true organic compound. But when Kolbe synthesized 

 acetic acid in 1845, and when other indisputably organic 

 compounds were made from their elements, then all agreed 

 that there was no essential difference between organic and 

 inorganic compounds, and that the former were nothing 

 but the compounds of carbon. At present many dye stuffs, 

 drugs and perfumes, which could once be obtained only 

 from plants, are made artificially on a large scale, and so 

 are many valuable carbon compounds that are not known 

 to occur ready formed at all. 



While the belief in an indispensable force of life thus 

 delayed for a time the progress of chemical synthesis, 



