F. W. WENT 77 



being involved in the growth process. To convince them of the physical 

 reality of the growth-promoting substance, I had to do the diffusion rate 

 experiments proving that the coleoptile tip extract was not an imponder- 

 able emanation, but something possessing the common attributes of 

 chemical substances. 



After the first enthusiasm for the growth hormone had worn off, 

 it became generally recognized that auxin was not a panacea or the 

 stone of wisdom, but simply that we had pushed back the frontiers of 

 science slightly, creating a much longer and more complex line demarcat- 

 ing fields of knowledge and the unknown. But at the same time it should 

 not be forgotten that even though the discovery of auxin complicated 

 knowledge about growth, it also produced links between many different 

 botanical fields of endeavor, and it brought chemists, horticulturists, 

 anatomists, physiologists, and many others together into a strong unity of 

 common interests. 



It is sometimes said that botanists are not sufficiently aware of the 

 practical implications of their work, or are staying too much aloof from 

 practical appUcations, or choose impractical problems to work on. All 

 these criticisms are either not based upon fact or are not germane. I can 

 assure you that at present only a small percentage of all the practical 

 auxin applications we were talking about twenty-two years ago have 

 materialized as yet. But a botanical laboratory is usually not rich enough 

 nor equipped with large enough experimental fields or greenhouses to 

 carry out the semipractical experiments necessary to apply theoretical 

 knowledge. 



The criticism of the impractical subject matter of botanical research 

 can easily be disposed of by pointing towards the auxin research. In the 

 early years all auxin work sprang from previous work on phototropism 

 in seedlings. This was considered so unimportant by more practically 

 incUned botanists, that the plant physiology textbook used most ex- 

 tensively in this country fifteen years ago did not even mention the word 

 tropism. And not only in this country, but also in Holland and elsewhere, 

 auxinolosists were criticized for their use of anemic etiolated seedlings. 

 We should be aware of the fact, however, that not until the advent of the 

 completely air-conditioned greenhouse or artificially lighted culture 

 room, were really conclusive experiments with fully mature plants pos- 

 sible. The basic principles of growth are not changed by the growing 

 conditions, but quantitative research requires reproducible plant ma- 



