NATURAL SCIENCE IN SEVENTEENTH CENTURY 263 



accepted and advocated by natural philosophers for the next 

 hundred years. It was not until new facts had been accumulated 

 which were not explained by the theory of Becher and Stahl, and 

 especially the fact revealed by the use of the balance, that sub- 

 stances calcined often gained weight (making it necessary to assume 

 that phlogiston possessed negative gravity, or " levity " since its 

 loss increased weight), that the theory became plainly untenable 

 and was abandoned. This, however, only happened late in the 

 eighteenth century, and before this time much progress had been 

 made in chemistry in other directions. Meanwhile, in spite of its 

 falsity, the theory of phlogiston had done good service. It had, 

 for example, effectually turned the attention of chemists away 

 from magic, from potable gold, and from the making of medicines, 

 to speculations on composition, decomposition, and chemical 

 change, topics not only more worthy but more fruitful. 



BEGINNINGS OF ORGANIC CHEMISTRY. Meantime, a kind of 

 organic chemistry was initiated by Hermann Boerhaave (1668- 

 1738), a physician of Leyden. In the seventeenth and eighteenth 

 centuries the term "organic" stood more than it does to-day for 

 the living world and its products which were then regarded as 

 things altogether apart from the lifeless or inorganic world. To- 

 day organic chemistry hardly means more than the chemistry of 

 the carbon compounds, but at that time it meant the chemistry of 

 bodies found in or produced by living things. Medical men had 

 long been interested in alchemy, and in more modern times in iatro- 

 chemistry, so that it was natural enough that Boerhaave, a physi- 

 cian, should undertake to subject organic substances to chemical 

 processes. And this he did, though more in the fashion of the 

 pharmaceutical, than the analytical, chemist of to-day. Boer- 

 haave was a famous teacher of medicine and of botany, and crowds 

 of students attended his lectures, thereby testifying to the now 

 rapidly growing popularity of scientific learning. His Elements 

 of Chemistry, published in 1732, was widely used and marks an 

 epoch in the history of chemistry. 



At about the same time, Dr. Stephen Hales (1677-1761), an 

 English clergyman of a strongly scientific bent, did similar work 



