RATIONAL FERTILIZATION. 173 



ining the conditions which tend to produce the best results with 

 existing varieties. Botanists have successfully assisted in ascer- 

 taining more reliable modes for the production of varieties ; the 

 phenomena of plant life are today far better understood than but 

 a few generations ago. Agricultural chemists have in late years 

 bestowed considerable attention on the investigation of the means 

 which promote a healthy and vigorous growth ; in the interest of an 

 economical production. 



The best experimental resources of scientists in both these 

 branches are evidently needed to solve in its various relations the 

 problem here under discussion. The observations of the physiolo- 

 gist by means of the microscope can gain importance only when 

 aided, as far as practicable, by the balance in the hands of the 

 chemist. 



The tendenc}' towards degeneration in many varieties of fruit 

 and of garden plants, if really existing to the extent claimed by 

 many writers on horticultural topics, must be a deep seated one, 

 and is most likely due to slowly acting adverse circumstances, of 

 various kinds. In some instances it ma}^ be the result of an un- 

 congenial climate ; in others of an unfit soil ; in others due to the 

 lack of a proper supply of desirable plant food ; in others again 

 to several of these adverse circumstances combined ; and may be in 

 all of them, to some extent at least, attributable to the weakening 

 influence of an artificial system of selection and propagation. 



Any attempt to generalize at the present stage of our observa- 

 tion will be considered, quite properly, injudicious. There seems 

 to^ be but one safe rule to follow, and this consists in studying 

 each case under well defined circumstances, and with all the scien- 

 tific experimental resources at our disposal, before advocating any 

 special course of treatment. 



After these introductory remarks to define my position regard- 

 ing the question under discussion, I take the liberty to invite your 

 attention to a short discourse on the state of our present informa- 

 tion bearing upon successful cultivation of existing varieties of 

 fruit and garden crops. 



'One of the first equirements for a healthful condition and a 

 subsequent successful propagation of any plant consists in adopt- 

 ing a well devised system of fertilization. 



We emphasize this requirement not only on account of its in- 

 trinsic importance, but for the further reason that its management 



