6 Early History of Botany [ch. 



3. Medicinal Botany. 



With the Revival of Learning, the speculative botany 

 of the ancients began to lose its hold upon thinking men. 

 This may be attributed to the curious lack of vitality, and 

 the absence of the power of active development, manifested 

 in this aspect of the subject since its initiation at the hands 

 of Aristotle. It had proved comparatively barren, because, 

 though the minds which engaged in it were among the 

 finest that have ever been concerned with the science, the 

 basis of observed fact was inadequate in quality and 

 quantity to sustain the philosophical superstructure built 

 upon it. It might have been supposed a priori that accurate 

 observation of natural phenomena needed a less highly 

 evolved type of mind than that required to cope with meta- 

 physical considerations, and hence that, in the development 

 of any science, the epoch of observation would have pre- 

 ceded the epoch of speculation. In actual fact, however, 

 the reverse appears to have been the case. The power of 

 scientific observation seems to have lagged many centuries 

 behind the power of reasoning, and to have reached its 

 maturity at least two thousand years later. 



Aristotle and Theophrastus arrived by the subtlest 

 mental processes at a certain attitude towards the universe, 

 and at certain ideas concerning the nature of things. They 

 attempted a direct advance in scientific thought by extend- 

 ing these conceptions to include the plant world. It was 

 an heroic effort, but one which could not ultimately form 

 a basis for continued progress, because, in its inception, 

 preconceived ideas had come first, and the facts of Nature 

 second. It seems to be almost a law of thousfht, that it is 

 the indirect advances which in the end prove to be the 

 most fertile. The progress of a science, like that of a 

 sailing boat, more often proceeds by means of "tacking" 

 than by following a direct course. 



In the case of botany, the path which was destined to 

 lead furthest in the end was the apparently unpromising 

 one of medicine. Various plants from very early times had 

 been used as healing agents, and it became necessary to 

 study them in detail, simply in order to discriminate the 

 kinds employed for different purposes. It was from this 



