THE DAWN OF BOTANICAL KNOWLEDGE 5 



to us had interests beyond the shop and the till, and 

 experimented on themselves with new drugs they had 

 discovered in the woods and the mountain glens. They 

 tested the effects of vegetable poisons and found, what 

 was rediscovered many centuries afterwards, that poisons 

 might be given in small doses without any evil results, 

 and that if the dose were gradually increased no injurious 

 consequences followed, even when the amount, had it 

 been administered in the first instance, would have proved 

 fatal. " The virtues of all drugs," writes Theophrastus, 

 " become weaker to those who are accustomed to them, 

 and in some cases become entirely ineffective. . . . For 

 it seems that some poisons become poisonous because 

 they are unfamiliar, or perhaps it is a more accurate 

 way of putting it to say that familiarity makes poisons 

 non-poisonous ; for when the constitution has accepted 

 them and prevails over them, they cease to be poisons, 

 as Thrasyas also remarked ; for he said that the same 

 thing was a poison to one and not to another ; . . . also, 

 besides the constitution, it is plain that use has something 

 to do with it." 



You must bear in mind that I am speaking of a period 

 many hundreds of years before the era of the printed book, 

 and hence all that the apothecaries of those days had to 

 depend on for their knowledge of the correct herbs from 

 which to prepare their " simples " was the laboriously 

 copied manuscripts of their predecessors or the oral 

 descriptions handed down from father to son or from 

 master to apprentice. What wonder then that the 

 physician often times complained of the inaccuracy of the 

 apothecary's " make up," and blamed him for the non- 

 success of his treatment of his patron's disease. Clearly 

 the one thing wanting was an authoritative pronounce- 

 ment of some kind on the morphological nature of plants, 

 and a description of their constituent organs in precise 

 terminology, that would form a means of accurately 

 diagnosing plants of medicinal value. Before the herbalist 



