736 



SCIENCE. 



[N. S. Vol. XV. No. 384. 



THE FUTURE OF VEGETABLE PATHOLOGY.* 

 On this occasion, as president of the 

 Ohio Academy, it is incumbent upon me 

 to deliver an address, presumably upon 

 some phase of the body of knowledge we 

 call science. Custom points no less un- 

 erringly to some topic along the lines of 

 one's chosen pursuit. Doubtless, without 

 any announcement a botanical heading 

 would be assigned to this occasion. For 

 various reasons it has seemed fitting to pre- 

 sent to you some thoughts on 'The Future 

 of Vegetable Pathology.' Certainly this 

 cannot be done without considering the 

 history of the rise and progress, nor with- 

 out discussing the present status of plant 

 pathology from the standpoint both of the 

 investigator and of the teacher. These 

 matters are likely to lead to estimates con- 

 cerning the rank of vegetable pathology 

 among the divisions of botanical science. 

 Concerning the speaker personally, it is 

 known to most of you that his pursuits are 

 along the line of the study and investiga- 

 tion of plant disease. 



Since it is in the cultural aspects of plant 

 life rather than in the original condition of 

 wild plants that pathology has claimed the 

 largest attention, we naturally look to that 

 phase for much of its history. The ad- 

 vance of our knowledge in this helpful line 

 has certainly been gratifying during the 

 closing decade of the nineteenth century. 



Plants, as dynamic factors, exhibit cer- 

 tain general and normal activities discern- 

 ible under widely different conditions of 

 environment, and recognizable in plants of 

 external dissimilarity; the study of these 

 normal activities leads us to plant physiol- 

 ogy. At the same time these plants in 

 their usual activities are impinged upon by 

 certain special and general phases of en- 

 vironment, by varying climatic conditions 

 embracing differences in the amounts of 



* Presidential address before the Ohio Academy 

 of Science, November 29, 1901, 



heat, light and hu^midity, exposure to dry- 

 ness in air or soil, as well as the encroach- 

 ments of animal life by the cropping of 

 herbivors or the fretting of insects. In 

 response to continuoi;sly acting stimuli of 

 this character the plants become modified 

 or adapted to the conditions surrounding 

 them; the study of this adaption leads to 

 ecology. 



Studying still these same plants as living 

 organisms, and either in their general f itnc- 

 tional activities or in their external and in- 

 ternal adaptations or in both, we find that 

 the course of life of the plant is by no 

 means always normal— instead of simple 

 turgor we may have intumescence or edema 

 (dropsy, as our physicians would say) ; in- 

 stead of the free water flow contemplated 

 through the conducting tissues we may 

 find the vessels closed. Not only this, ex- 

 ternal and internal parasites may attack 

 any and all organs of the plants, intercept- 

 ing light and heat, absorbing, destroying or 

 diverting the iisual nutritive substance, 

 penetrating and transforming essential or- 

 ganic tissues, and even totally preventing 

 the attainment of the reproductive func- 

 tions ; these parasites may lie in wait in the 

 soil, be wafted in the winds or be sown 

 with the seed of the husbandman. Other- 

 wise incapable of striking expression by 

 external signs, the plant may find itself 

 fixed in a soil with inadequate or unsuit- 

 able or even injurious substances con- 

 tained therein ; accordingly there is stunted 

 growth, reduced vigor or manifest ill health 

 indicated by fruit or foliage. Abnor- 

 malities are seen in such and in other 

 ways; their study just as certainly leads 

 us to vegetable pathology. 



Pathology is then at least tentatively 

 ranked coordinately with physiology and 

 ecology among the divisions of botanical 

 science which have to do with plants in 

 their life relations. No one of these 

 divisions just enmnerated, more than an- 



