No. 6. DEPARTMENT OF AGRICULTURE. S07 



the natives were found using phosphatic marls to obtain better 

 crops. But these practices were the result of accident or mere 

 observation, and were not based upon any knowledge of the rela- 

 tions of soils, fertilizers and plants. The same is true of the prac- 

 tice of the Indians of putting fish in their hills of corn, as observed 

 by the early settlers of America. 



That there were no very definite ideas in the minds of the early 

 users of phosphates or other mineral plant fcods, at least ideas 

 which correspond with the present existing theoiy of the relations 

 of plants to mineral plant foods, is evidenced by the fact that 

 the Prussian Academv of Sciences, in the vear 1800, offered a 

 prize for an investigation to decide whether the mineral matters 

 found in plants are taken up from the soil or whether they are 

 produced in the plants themselves by vital power. This question 

 was treated by Schroader, whose decision was in favor of the latter 

 opinion. 



This opinion, though probably quite generally held, did not re^ 

 main long in force, for Saussure, in 1804, declared that the mineral 

 matter of humus contributed in a certain degree to fertility, since the 

 same minerals are found in the ashes of plants. Sir Humphrey Davy 

 was the first to consider the mineral constituents essential for the 

 development of plants, as is evidenced by his statements in Ele- 

 ments of Agricultural' Chemistry, London, 1814, to the effect that: 

 "The chemistry of the simpler manures (the manures which act 

 in very small quantities, such as bone dust, gypsum, alkalies and 

 various saline substances), has hitherto been exceedingly obscure. 

 It has been generally supposed that these materials act in the vege- 

 table economy in the same manner as condiments or stimulants in 

 the animal economy and that they render the common food more 

 nutritive. It seems, however, a much more probable idea that they 

 are actually a part of the true food of plants, and that they supply 

 the kind of matter to the vegetable fiber which is analogous to the 

 bony matter in animal stomachs." Springel, in his Theory of Manur- 

 ing^ published in 1839, was the second to express an opinion to this 

 same effect. He said: "We can accept it as an indisputable fact 

 that mineral matters found in plants are real nutrients for them, 

 and that it is not their action upon humus which make them im- 

 portant, since gypsum, potassium, sulphate and calcium phosphate 

 do not at all act upon the humus." 



Closely following the statements of Springel, came (in 1840) the 

 published results of the researches of Justus von Leibig. Leibig's 

 results laid the foundation for our present agricultural chemistry, 

 and entitled him to the designation of the "Father of Agricultural 

 Chemistry." 



