December 12, 1902.] 



SCIENCE. 



923 



into, and a considerable amount of infor- 

 mation as to what minerals are advantage- 

 ously applied to the soil in which particular 

 plants are to be sown has been acquired. 

 A kind of empirical knowledge is thus in 

 our possession, in some respects a very de- 

 tailed one, quantitative as well as qualita- 

 tive records being available to the inquirer. 

 But elaborate as have been the researches 

 in these directions, and costly and trouble- 

 some as the investigations have been, they 

 have been hardly, if at all, more than em- 

 pirical. Till quite recently the physiolog- 

 ical idiosyncrasies of the plants round 

 which all these inquiries centered were 

 almost entirely ignored. No serious at- 

 tempt was made to ascertain the way in 

 which a plant benefited by or suffered from 

 the presence of a particular constituent of 

 the soil. What influence, for instance, has 

 potassium or any of its compounds upon 

 the general metabolism of the plant? Does 

 it affect all its normal nutritive processes, 

 or does it specially associate itself with 

 some particular one? If so which one, and 

 how does the plant respond to its presence 

 or absence by modifying its behavior? So 

 with phosphorus again ; hardly any investi- 

 gation can be made into the nutritive proc- 

 esses of a plant without this element be- 

 coming more or less prominent. In some 

 eases the empirical results already referred 

 to show an enormous influence on the crop 

 exerted by soluble phosphates in the soil 

 or the manure applied to it. But what 

 can yet be said as to the role played by 

 phosphorus or by phosphates in the meta- 

 bolic processes in the plant? Further, how 

 do different plants show different peculiar- 

 ities in their reaction to these various con- 

 stituents of the soil? ' For the advance of 

 agriculture the study of the plant itself 

 must now be added to the study of the soil. 

 The fact that it is a living organism pos- 

 sessing a certain variable and delicate 

 constitution, responding in particular ways 



to differences of environment, capable of 

 adapting itself to a cei'tain extent to its 

 conditions of life, dealing in particular 

 ways with different nutritive substances, 

 must not only be recognized, but must be 

 the basis for the researches of the future, 

 which will thus supplement and enlarge 

 the conclusions derived from those of the 

 past, in some respects correcting them, in 

 others establishing them on a firmer basis. 



In pressing upon the younger school of 

 botanists the importance of this line of 

 research, I do not wish to minimize the 

 difficulties that accompany it. Difficulties 

 of method assume considerable magnitude, 

 for we have here no question of section cut- 

 ting and microscopic examination. Vege- 

 table physiology is allied very closely to 

 other sciences, and research into its mys- 

 teries involves more than a preliminary ac- 

 quaintance with them. Especially must 

 one point out the importance, indeed the 

 necessity, of acquaintance with a certain 

 range of organic chemistry and with chem- 

 ical methods of work. In certain direc- 

 tions, too, physics are as much involved as 

 chemistry in others. The bearing of these 

 sciences in particular directions will be re- 

 ferred to later. 



I fear another obstacle stands at the 

 threshold of research which looks suffi- 

 ciently formidable. The so-called funda- 

 mental facts of vegetable physiology have 

 been laid down with sufficient dogmatism 

 in text-books by many writers whose names 

 carry with them such weight that it ap- 

 pears almost heresy to question their state- 

 ments. We have been content to accept 

 many things on the authority of the great 

 workers of the past, with the result that 

 the advance of knowledge has been hin- 

 dered by such acceptance of what were 

 deemed facts, but were really inaccuracies. 

 We may refer, for instance, to the state- 

 ment made by Boussingault, and accepted 

 by most botanists ever since his time, that 



