BOTANY AND MEDICINE 445 



mental pharmacognosists in plant chemistry, biochemistry, and physiology. 

 As a result pharmacognosy has now begun to deal more extensively than 

 before with these aspects of experimental botany as they can be related to 

 medicinal plants. This change has also been greatly reflected in the teaching 

 of pharmacognosy in pharmacy schools, and it can be observed in the pub- 

 lications and textbooks of more modern pharmacognosists. This has brought 

 experimental botany somewhat closer to experimental medical pharmacology. 

 Botanical drugs reached a peak in the numbers that were employed in medi- 

 cine and pharmacy at the turn of the 20th century. At that time the major 

 contents of pharmacopeias and formularies of many nations, including the 

 United States Pharmacopoeia, the British Pharmacopoeia, British Codex, and 

 National Formulary of the American Pharmaceutical Association were the 

 descriptive standards of crude plant drugs and some of their medicinally 

 valuable constituents. 



Beginning with the time of Wohler, the distinguished German chemist, 

 early in the 19th century, and with the advance in medical pharmacology, 

 which began almost one hundred years later under the stimulus of John 

 Jacob Abel, much of the empiricism that had been formerly applied to the 

 drug action of plants as medicines had given way to rationalism. Today drugs 

 from plants which are to be used in the treatment of disease must have had 

 tried and trusted chemical, pharmacological, and clinical scrutiny. Many of 

 the older botanicals, galenicals, and crude biological and mineral mixtures 

 have, in general, failed to survive the exacting tests of modern methods for 

 evaluating drugs. The very nature of their composite make-up — ballast plus 

 biologically active components when the latter can be found — has placed 

 them beyond the realm of critical evaluation. How much more exacting it is 

 for a chemist and pharmacologist to demonstrate the properties of a pure 

 and single crystalline compound, regardless of its source. Therefore the use 

 of a great number of plant drugs per se in medicine has significantly de- 

 creased. On the other hand, the "pharmacotherapeutics" of several purified 

 plant constituents (digitoxin, cocaine, quinine, caffeine, morphine, codeine, 

 reserpine, ergotamine, etc.) has remained important to medical science. 



The age of "pharmacotherapeutics," which means the study of the uses 

 of drugs in the treatment of disease, has followed the ''pure compound line." 

 It is based, wherever possible, upon a correlation of pharmacological action 

 with pathological physiology or the microbiological aspects of disease. To 

 a great extent it has been based also upon relationships between chemical 

 structure and pharmacological action, the so-called "molecular structure-activ- 

 ity" relationship. Out of this development has come the age of chemotherapy, 

 the latter stimulated in the late 19th century by the contributions of the 

 German biologist Paul Ehrlich, his "magic bullet" and antisyphilitic arsenicals. 

 Botanists will recall that this period was about the same time as the great 

 contributions to that science of Charles Darwin, Engler and Prantl, and Ed- 



