THE LIME-MAGNESIA RATIO 127 



the very best kind of an argument for the introduction into the 

 Ume-magnesia ratio problem of other factors which are quite 

 different from the antagonism between calcium and magnesium 

 (which no one \^•ill deny exists) that may regulate the growth and 

 even affect it, seriously, of the plants under consideration, with- 

 out regard to any specific ratio between lime and magnesia. 



Likewise, Loew's objection to Meyer's investigation is one that 

 is hardly tenable because the number of plants used per pot and 

 the time of harvest to which Loew objects, are sources of error, 

 the like of which might be found in other aspects of pot or water 

 culture experiments carried out by Loew, or anybody else. So, 

 also we may cite Loew's objections to Gile's investigations on 

 the basis that plants were used which were lime-loving plants 

 and that therefore they were not affected by excessive quantities 

 of hme, and hence the lime-magnesia ratio became a question of 

 minor importance \vith such plants. But Gile continued his 

 work with other plants, such as rice and bush beans, which were 

 differently affected by Hme, since they were not known to pro- 

 duce acids equivalent to the citric acid of say, the citrus tree, 

 for precipitating the calcium, and yet no evidence was found that 

 a relationship existed between the growth and welfare of the 

 beans and rice and the ratio between lime and magnesia in the 

 soil, or in other media employed. 



Studying the subject generally, one is constrained to wonder 

 why we should seek so far fetched an explanation of the antago- 

 nistic effects of calcium to magnesium and vice versa, so far as 

 they exist, when we have the general principle of antagonism be- 

 tween ions as one of much firmer establishment by reason of a 

 much wdder test and one which in the light of all that we know 

 in plant physiology and in chemistry, is accompanied by much 

 greater cogency and rationahty. That the toxic effect of an ex- 

 cess of magnesium salts can be neutralized by other materials 

 than calcium we have ample evidence in the investigations of 

 many plant physiologists, among them Osterhout, McCool, 

 Miyake, the writer, and others working in a less elaborate way 

 on that subject. So, too, we have ample evidence on the an- 

 tagonistic influence of many other salts to calcium when calcium 

 is present in form or quantity of a character to be toxic. 



sMi 



\>^ 



