92 CHARLES B. LIPMAN 



ship with Corso^^ and the other with Siniscalchi.^o In the first 

 of these papers, an account was given of experiments which are 

 said to confirm the work of Loew and the Japanese investigators 

 which is above reviewed. The best ratio for wheat, rye, oats, 

 rice, and barley is said to have been 1: 1 (CaO: MgO), whereas 

 2 : 1 (CaO : MgO) was best for maize, onions, spinach, flax and 

 cabbage. For the Leguminosae 3 : 1 (CaO : MgO) was shown to 

 be the best. 



In the second paper, experiments are reported with optimum 

 nutritive solutions and pot cultures. From the solution work, 

 which constituted a continuation of Bernardini's previous work, 

 the conclusion is drawn that phosphoric acid absorption by plants 

 depends on the lime-magnesia ratio. As the ratio increases in 

 favor of the lime, phosphoric acid assimilation decreases and 

 vice versa. From the pot cultures in which lupines were studied, 

 the conclusion is drawn that not the absolute, but the relative or 

 proportionate amount of Hme and magnesia are responsible for 

 toxicity, or lack of it, owing to the fact that the two ions are ab- 

 sorbed by the plants in the same ratio as they are present in the 

 soil. 



In 1911 Warthiadi-i pubHshed a dissertation on the ''varixtion 

 of plants under the influence of lime and magnesia." The work 

 was carried out in both solution and sand cultures. Warthiadi 

 claims to have confirmed the findings of Loew and Willstatter, 

 according to which an excesss of magnesia injuriously affects 

 the yield of straw, whereas an excess of lime similarly affects the 

 yield of grain. Warthiadi also discusses other physiological fac- 

 tors which are concerned with the assimilation of the chemical 

 elements essential to plant growth and finally concludes by sup- 

 porting the idea that there is a necessity for a ratio of 1 : 1 (CaO : 

 MgO) in growdng cereals. 



1* Ann. R. Scuola, Sup. Agr. Portici, vol. 7, p. 16. Cited from E. S. R., vol. 



21, p. 30, 1909. 



20 Ann. R. Scuola, Sup. Agr. Portici, vol. 8, p. 19. Cited from E. S. R., vol. 



22, p. 433, 1910. 



21 Diss. R. Tech. Hochschule Munchen, 1911, p. 35. 



