the character of the ash constituents of fruits, and to study also the 

 relations which apparently exist between the variations in the com- 

 position of the former, and the quality of the latter, for the purpose 

 of furnishing information needed for the successful introduction of a 

 rational system of fertilization of onv fruit-hearing x:>lants.'" 



These invesrigations have been carried on since without serious in- 

 terruption, as far as the limited resources of past years for experi- 

 mental work of that character have permitted. The scarcity of 

 previous systematic chemical inquiries into the relations existing 

 between the kind and the amount of available plant food in a pro- 

 ductive garden soil or orchard, and the absolute and relative quantity 

 of the various soil constituents contained in the fruits and the garden 

 crops raised upon it, rendered it necessary to grow them under well 

 defined circumstances, to obtain material fit for comparative analyses. 

 The necessity of adopting that course of action became still more 

 apparent, when considering the extraordinary influence — quite gener- 

 ally conceded — of soil, location and season on the quality of these 

 crops. Products raised by the aid of different manurial substances, 

 within the same season, upon a similar soil, and of a corresponding 

 stage of growth^ had to be secured for the examination, to impart a 

 scientific and practical value to the analytical results. 



It is a well-known fact that the absolute amo^mt of the mineral 

 constituents of plants of the same variety and of one and the same 

 species even may differ widely, yet as a rule this circumstance does 

 not necessarily alter the general character of the plants. A change, 

 however, in the relative jiroportion of the various mineral constituents, 

 as potassa, lime, etc, rarely has been noticed without having affected 

 the quantity of some of the organic constituents, as sugar, starch, 

 acids, etc. The fact that the essential mineral constituents (potas- 

 sium, calcium, magnesium, iron and phosphorus), of our farm plants 

 cannot replace each other beyond a certain extent in the vegetable 

 economy without endangering their life, points towards a specific 

 function of each of them in the growth of these plants. We have 

 learned by experimental observation what elements are indispensable 

 for a healthy growth, and a successful reproduction of these plants. 

 It remains for us then to ascertain the particular function of each of 

 the above elements in the life of plants. The more we learn of the 

 specific functions of each essential mineral constituent of plants, the 

 better will we be prepared to perfect our system of manuring, to cul- 

 tivate with a view of developing desirable qualities in the crops, and 



