CONVENTION OF AMERICAN A.GBICULTUBAL COLLEGES. 33] 



»Dr. II. J. Wheeler made some suggest ions regarding profitable lines 

 of research in connection with soils, including studj of chemical means 

 of differentiation of the forms of phosphoric acid in soils, influence of 

 soil treatment on the biological processes of the soil and the growth of 

 plants, max iin um limits of application of lime, in Hue nee of the growth 

 of one plant upon the growth of it- successor upon the same soil, 

 influence of soil texture upon the growth of different plants, availability 

 of plant food, the relative avidity with which different plant- take up 

 soil potash and soda, and the reliability and applicability of Loew's 

 hypothesis regarding a accessary fixed ratio between lime and 

 magnesia in product ive soils. 



In the discussion of the subject of demonstration work. Director 

 Thorne explained the Ohio system of (1) test farms on which experi 

 mental work is carried on in different parts of the State; (2) coopera 

 tive experiments with farmer-, taking up simpler phases of station 

 work, and intended primarily to develop farm experimenters in each 

 locality, and (3) special arrangement for particular piece- of work. 

 Some feature- of the work done under this system are experimental 

 and in part maintained by Federal funds; a large part i- purely 

 demonstration work and is maintained by State fund- provided for 

 that specific purpose. The importance in cooperative work of reliev- 

 ing the fanner from pecuniary responsibility and of maintaining strict 

 supervision of tin 1 work through station officers was (jointed out. The 

 speaker urged the need of extension of demonstration work. 



Dr. Hopkins explained the system of combined experimental and 

 demonstration work followed in Illinois on the farms controlled by 

 long-time lease or purchase on the various typical soil area- of that 

 State. Prof. L. C. Corbett drew a sharp distinction between experi- 

 mental work and demonstration work, holding that the latter should 

 have as its prime object the teaching- of remunerative method- of 

 farming, as illustrated in the work of the Department demonstration 

 farms in the cotton belt. Similar views were expressed by Director 

 ( !. D. Smith, who cited various illustration- of way- in which the sta- 

 tion had been instrumental in introducing more profitable farm prac 

 tices in Michigan by mean- of demonstration experiments. 



Dr. \Y. II. Jordan, of New York, thought that agricultural knowl- 

 edge passed through three stages in reaching the farmer, (h labora- 

 tory investigation, (2) test in practice. (.".) general introduction. 

 Experimental work end- with the second stage. The third i- purely 

 demonstration work, and is not the province of the -tat ion- under the 

 Hatch Act. Director Hill-, of Vermont, thought discovery to be the 

 primary object of the stations, and that demonstration work was out- 

 side their province. Dr. Wheeler believed the discovery and test in 

 practice of scientific truth the proper functions of the station. The 

 dissemination of result- by demonstration and like means he held to 



