56 



SCIENCE. 



[N. S. Vol. XVI. No. 393. 



more, shown the futility of attempting to 

 solve such problems along one line of cleav- 

 age, for it cannot be done with any degree 

 of satisfaction. 



Aside from the problems mentioned, the 

 field for applied work in plant nutrition is 

 large. The physiological role of mineral 

 nutrients in plants is little understood, 

 and the effects of mineral nutrients on 

 growth, singly and combined, should be 

 explained. The power to control profitable 

 plant production through a better knowl- 

 edge of plant foods is recognized, but there 

 is yet much to do in the matter of making 

 clear little known or obscure questions on 

 this subject. In the problems connected 

 with the acquisition of nitrogen, however, 

 are to be found some of the most important 

 practical questions in this field. The re- 

 sults already accomplished in this direc- 

 tion, through the use of proper nitrifying 

 ferments, have not been as successful as 

 was anticipated, but this does not indicate 

 that future work may not be made more 

 profitable. There is much to be done in 

 the way of investigating the life history 

 of bacteria inhabiting the root tubercles 

 of legumes, for unless such questions are 

 better understood it will not be practical 

 tc apply our knowledge in any far-reach- 

 ing way. The time will doubtless come, 

 however, when our knowledge of the nitri- 

 fying organisms will be sufficient to en- 

 able us to apply, in a much broader way, 

 the use of pure cultures of such organ- 

 isms in general field work. Already encour- 

 aging results have been obtained in this 

 direction, and steps, are being taken to 

 extend the practical application of these 

 results as rapidly as circumstances will 

 warrant. The future success of this work 

 will no doubt depend, in large measure, 

 upon the ability to properly grow the nitri- 

 fying organisms in large quantities and at 

 an expense which will not curtail their 

 use; and then to be able to distribute the 



organisms in such a way that the farmer 

 himself may iise them at little expense, 

 but with sufficient profit to pay for his 

 trouble. It will be seen, therefore, that 

 while these may appear as simple problems 

 when looking at them from the purely utili- 

 tarian view, there is much work to be done 

 in the laboratory, under rigid scientific 

 conditions, before satisfactory conclusions 

 caxi be reached. 



It is in connection mth the problems 

 bearing on plant breeding, and the selec- 

 tion of plants better adapted to meet the 

 special requirements, that some of the 

 broadest questions of applied botany can 

 be brought to bear. "While, as already ex- 

 plained, plant breeding is more or less of 

 a composite science and, to a certain extent, 

 an art, physiology is, after all, the basis 

 for most of the woi'k. There is much need 

 for further research work in the field of 

 reproduction and heredity, especially with 

 a view to obtaining light on many prac- 

 tical questions which are bound to come 

 up within the next few years if applied 

 investigations are to have their proper 

 place. Admitting the necessity of these, 

 it would seem that some of the more prac- 

 tical problems that must be considered 

 within the near future Avill have to do with 

 obtaining light on such matters as the se- 

 curing of plants adapted to particular pur- 

 poses and to particular regions. As popu- 

 lation increases and competition in all lines 

 of agricultural production becomes keener, 

 the need for securing plants better adapted 

 to certain conditions and which can be pi-o- 

 duced at a minimmn expense, will become 

 greater and gi-eater. In the South there 

 is already felt the urgent need for im- 

 proved kinds of cotton varieties that will 

 give greater yields and finer staple, in or- 

 der that cheap labor of foreign coiuitries 

 can be competed with. There is also a 

 demand for improvement in other plants 

 adapted to the South, which will en- 



