304 "Wisconsin State Hoeticultueal Society. 



to plant life took place during the time which passed between the 

 first publication of the investigations of De Saussure and Davy, 

 and those of Liebig. The year 1840 is, on this account, usually 

 cited as the beginning of a new era in the history of agriculture 

 and its associated branches. It is justly claimed as one of the 

 most valuable services which Liebig has rendered to scientific and 

 practical agriculture, that he demonstrated by the aid of previous 

 investigations, as well as his own, the true connection which exists 

 between soil and plant, and the intrinsic value of the mineral con- 

 stituents in the growth of plants. 



Accepting, as we do, Liebig's teachings that a certain kind and 

 a certain amount of mineral elements are indispensable for the 

 complete development of a plant through all its various stages of 

 life, and that, in case the ash constituents of the plant are not 

 supplied in due time, the plant may come to blooming, yet cannot 

 produce a perfect seed, it becomes quite obvious that the time- 

 honored practice of using wood-ashes, or lime, or marl, etc., above 

 referred to, for manurial purposes, presents quite a different aspect 

 to us from any that it could possibly claim in previous ages; for, 

 knowing now, in consequence of previous careful analysis of the 

 ashes of its particular kind, what elements the perfect plant con- 

 tains, the practical experience of the past receives a more intelli- 

 gent interpretation of its results, and future success a better 

 chance. 



The direction which Liebig's genius has given to the study of 

 plant growth, with reference to its application in practical agricult- 

 ure, has been pursued since with an interest and success unparal- 

 leled in the history of any province of science. Practice and 

 science have already for years worked hand in hand to stud}-^ the 

 influence of physical and chemical agencies on the production of 

 vegetable growth, and to reconcile real and apparent differences 

 of experimental results. Much has been accomplished — too 

 much, in fact, to find here a mere passing enumeration; yet much 

 more remains to be learned to free our present system of manur- 

 ing from that degree of uncertainty which a reasonable prospect 

 of success still demands. The unsatisfactory condition of our cur- 

 rent modes of fertilizing our lands is, in a great measure, due either 



