94 CHARLES B. LIPMAN 



the negative experiments, it may be added that the experiments 

 of Voelcker just referred to have been further ampHfied and em- 

 phasized in the following report of the Royal Society, Volume 

 74. These, and other investigations, have all tended to confirm 

 the hypothesis of the lime-magnesia ratio. Loew" has even 

 gone so far as to suggest that anaemia and other physiological 

 troubles in animals and man observed in Porto Rico, are due in 

 part to a deficiency of hme in the food products, and especially 

 in rice. 



THE NEGATIVE INVESTIGATIONS, OR THOSE SHOWING LITTLE OR 

 NO SUPPORT FOR THE LIME-MAGNESIA RATIO HYPOTHESIS 



In 1901 von Portheim^^ reported a study after the fashion of 

 Loew's earlier experiments of the role of lime in the growth of 

 certain plants. He concludes from these experiments that the 

 presence or absence of lime is immaterial for the seedlings of 

 cress, sorrel, rye, barley, wheat, oats, larch and pine. He points 

 out, however, that when certain untoward influences affect these 

 seedlings, the presence or absence of lime may determine the 

 rate and degree of injury. For example, when lime is absent, 

 the effects of heat on seedlings are noted to be much more serious 

 than in its presence. 



In 1903 GosseP*^ carried out a series of investigations with 

 water cultures and soil cutlures. The plants which he experi- 

 mented with- — barley and horse beans — were found to grow well 

 with more magnesium present in the culture than calcium. The 

 highest yields in water cultures were obtained with 0.4 part of 

 hme to 1 part of magnesia. This is a reversal of, and contrary 

 to the ratio which Loew claims to have established. In passing, 

 it may be said here that Loew" objects to the experiments of 

 Gossel on the ground that the latter used secondary potassium 

 phosphate in his experiments as a source of potash and phos- 

 phoric acid, whereas Loew used the primary form. The objec- 



2* Rpt. Physiologists, Porto Rico, p. 13-17, 1913. 



"Sitzber. K. Akad. Wiss. Math. Natunv. CI. Vienna, vol. 110', p. 113. 

 " Chem. Ztg., vol. 27, p. 952. Cited from E. S. R., vol. 15, p. 564, 1903-04. 

 " Chem. Ztg., vol. 27, p. 1221. Cited from E. S. R., vol. 15, p. 760, 1903-04. 



