Antitoxic Action of Certain Bases 127 



in various solutions when resistant glass beakers are substituted for 

 ordinary glass tumblers as containers of the culture solutions. The 

 results showed conclusively that the differences are not recognizable. 

 The use of the tumblers as receptacles for the solutions is thus justified. 

 In order to support the seedlings and to prevent evaporation the tumblers 

 were covered with paraffined wrapping paper, made secure by means of 

 rubber bands. Holes were made in the paper and the radicles were in- 

 serted through these into the solutions below. The tumblers were also 

 slipped into black paper shells. 



If the tops of the seedlings grew to a height of three inches they were 

 supported by means of wires carrying rings which projected directly 

 above the tumblers. These wires held the tops of the plants upright 

 and thus afforded uniform conditions of light. 



The duration of the experiments was twenty-one to thirty days. Fre- 

 quent observations were made until the end of the period, when generally 

 the final notes were taken. The original amount of the solution was 

 maintained by the addition of distilled water. The writer has found this 

 method satisfactory. In all cases the essential data are given in the 

 tables or in the text In connection therewith. 



relation between calcium and magnesium 

 Review of important field work 



The calcium-magnesium relation of soils has been shown to be a most 

 important one in crop production. Previous to the formulation of the 

 view that there is a definite lime-magnesia ratio for maximum plant growth, 

 many contradictory reports existed respecting the benefits or injuries from 

 the application of lime and magnesia to soils. 



As early as 1814, Davy (1814) discussed the injury that magnesia some- 

 times produces on crops. He wrote, '^ On mixing some calcined magnesia 

 with soil in which different seeds are sown, it is found that they either die 

 or vegetate in a very imperfect manner." He also states " that lime from 

 magnesia limestone may be applied in large quantities to plots, and where 

 lands have been injured by the application of too large quantities of mag- 

 nesia lime, peat will be a proper and efficient remedy." 



The deleterious influence of a high magnesium lime was reported by the 

 United States Commissioner of Agriculture in 1876. Parts of a field fer- 



