494 



SCIENCE. 



[N. S. Vol. XIX. Xo. 4S2. 



else than eontiuue to kaleidoscope the old 

 and familiar matter. Yet the aim of ecol- 

 ogy is perfectly definite, and as lofty as 

 any in science, being nothing less than to 

 explain why each plant is what it is, where 

 it is and in the company it is. Why then 

 do we fall so far behind our ideal? The 

 reason is perfectly plain. "VVe have 

 reached, and long since, the point at which, 

 with our purely observational methods, the 

 law of diminishing retui-n applies strongly 

 to the investigation of the subject; and 

 further substantial advance is now possible 

 only throi^gh the aid of some new method. 

 Further, the nature of this new method is 

 equally plain, and it is only practical limi- 

 tations of time and cost which keep us 

 from utilizing it. It lies in the precise 

 experimental study of the physics of the 

 environment, and of the physiological life 

 histories of particular plants, with the in- 

 vention of a mode of recording the results 

 in a form to permit the one to be corre- 

 lated with the other. There must go along 

 with this an improvement in our ecological 

 reasoning; or rather, to be correct, real 

 reasoning, involving logical proof, must 

 be substituted for those speculative yokings 

 of conspicuous effects with prominent pos- 

 sible causes which too often take the place 

 of reasoning in our ecological works. 



For this indispensable dual study of en- 

 vironmental physics and adaptational 

 physiology we have some, though no great, 

 foundation. Our knowledge of the phys- 

 ics of the atmosphere and our methods 

 for investigating it are, thanks to meteorol- 

 ogy, fairly satisfactory, but we need a new 

 form of record for meteorological data 

 which will make them more directly avail- 

 able than at present in the interpretation 

 of ecological phenomena. Our knowledge 

 of the physics of the soil, however, involv- 

 ing factors more important in the aggre- 

 gate than those of the atmosphere, is com- 

 paratively scanty, while methods for its 



exact study are only beginning to be de- 

 veloped. The exact study of soil physics 

 (using this term broadly) seems to me the 

 greatest present single need of ecology. 

 Turning to the other member of the eco- 

 logical equation, the plant, whose physio- 

 logical powers and limitations determine its 

 adjustment to particular environments, it 

 appears to be a fact that no attempt has 

 yet been made to apply our considerable 

 physiological knowledge, and our excellent 

 physiological methods, to the elucidation of 

 the physiological life-history of any one of 

 even the important forms constituting our 

 vegetation. Yet it is only through such 

 studies, for which some new appliances and 

 methods must be developed, that we can 

 hope to understand not only the factors in- 

 volved in the adaptations of the particular 

 form to its environment, but also the na- 

 ture of the all-important subject of plant- 

 competition, which determines how the 

 forms build up a vegetation. No doubt the 

 subject will iiltimately work itself out as a 

 series of ecological life histories, in which 

 the physiological powers and limitations of 

 each plant will be expressed in a system of 

 standard units or formulte with all the 

 definiteness of the taxonomic terminology 

 of the present day. But such studies as 

 these can not be made by busy teachers 

 who can give to them only a vacation leisure 

 and a scanty equipment. They can be 

 made only by trained investigators who, 

 with ample time, expert assistance, and 

 properly equipped field laboratories, can 

 give themselves wholly to it. Into this 

 fruitful field we welcome the Carnegie 

 Desert Laboratory; may its kind increase 

 until we have not only mountain, jungle, 

 seaside and forest laboratories, but also an- 

 other form which can be moved from place 

 to place in pursuit of the most pressing 

 problems. 



Such seems to me the status of plant 

 ecology at present and the direction it miist 



