July 23. 1917 Effects on Growth and Reproduction of Rations 185 



Consequently we imposed upon the normal corn ration a mixture of 

 either the carbonates or the organic salts of the bases in the same quan- 

 titative make-up as was used with the wheat and wheat-straw ration. 

 The quantity used for 14 pounds of the ration was also identical with 

 that imposed upon a wheat-grain and wheat-straw ration described in 

 an earUer part of this paper, and consisted of 13 gm. of calcium car- 

 bonate, 21 gm. of magnesium carbonate, and 51 gm. of potassium car- 

 bonate. The proportion of organic salts added was 40 gm. of calcium 

 lactate, 60 gm. of magnesium citrate, and 80 gm. of potassium citrate. 



This quantity of bases imposed on a com ration was arbitrarily chosen, 

 but was probably sufficient in quantity to test adequately the theory 

 proposed. In some cases only magnesium salts were added, but in quan- 

 tities equivalent to the basicity of the mixture of salts used. There has 

 been suggested many times in both fields of plant and animal nutrition 

 that the relation of calcium to magnesium must be rather definitely pro- 

 portioned if optimum growth is to be expected. For different plants dif- 

 ferent calcium-magnesium ratios have been proposed as most favorable, 

 although the entire theory, at least in some of its quantitative aspects, 

 is at present on trial. In animal nutrition it has been suggested that 

 disturbances may arise through an excess of magnesium to calcium in 

 the ration. For example, miller's disease of horses is attributed to the 

 use of wheat bran, and especially to the fact that bran contains an excess 

 of magnesium to calcium. The problem of antagonism of elements and 

 salts is an important one for both plant and animal nutrition, but how 

 far regulating mechanisms at cell surfaces in both plants and animals 

 come into play must always be considered before we adopt the idea of 

 the necessity for optimum behavior of a quantitative relation of the ions 

 or molecules. In the all-corn ration calcium oxid and magnesium oxid 

 stood approximately in the relation of i to i . In the wheat and wheat- 

 straw ration the same relation existed. For purposes of orientation we 

 have imposed upon the com ration magnesium salts (181 gm. of magne- 

 sium citrate per 14 pounds), which would make the calcium-magnesium 

 relation approximately i to 2 



In Table V these records are shown. 

 98975°— 17 3 



