CAN LTTIIIA BE A CONSTITUENT OF I'LANT FOUD ? 229 



height of 6' 3", and the " medeah " wheat 5' 2". On the 

 " spring " wheat there were four, and on the '" medeah " wheat 

 live ears. The ears of hoth kinds of wheat were fonnd to be 

 absohitely empty ; not a vestige of grain was in the ears. A 

 very large number of water-cuhures had been carried out in 

 previous years with normal solutions under the same conditions, 

 and in each case a fair number of ears was formed, and an 

 abundant crop (»f grains iiarvested. 



From the restilts of these experiments one cannot help 

 coming to the conclusion that the presence of lithium compounds 

 prevented the formation of seed; and also that the signs of 

 decline of growth, which were noticeable after the end of Sep- 

 tember, are attribtttable to the presence of the lithitmi com- 

 potuid, because in normal solutions vigorous growth is main- 

 tained to the end of the period of vegetation. 



According to the analyses made of the air-dry plants, the 

 " spring " wheat yielded as much as 14.85 per cent., and 14.03 

 per cent, of ash, whilst the " medeah '" wheat yielded y.41 per 

 cent, and 9.91 per cent, of ash. These results are higher than 

 the ordinary average percentage of ash in wheat, virj., 6.1 to 7 

 per cent. The plants had evidently freely absorbed the saline 

 ingredients of the solutions. 



The qtiantity of ash obtained b_\' the incineration of the four 

 plants was only small and insufticient for a gravimetric deter- 

 mination of lithitmi, the presence of which in the ash could 

 readily be ascertained by spectroscopic examination. But the 

 diilerent degree of brightness of the light of the lithium lines in 

 the comparative spectroscopic tests evidently proved that 

 "medeah "' Avheat had absorbed a larger proportion of the lithitmi 

 compound than the " spring " wheat. 



These experiments show that lithium compounds in the 

 presence of potassittm compounds do not infltience the growth 

 of Avheat in water-cultures dtiring the first period of vegetation, 

 whereas in the later period the growth of the plants is rather 

 retarded and the formation of grains prevented. 



[lie experiments are being continued with modified w'ater- 

 cuhure -olutions and on prepared soil. They will also be carried 

 out witli potatoes planted on soil supplied with an amount of 

 lithium compounds equal to the ([uantity of potash in that soil. 



The subject is not only of l)iocheniical, but also of thera- 

 peutical interest, since lithium in starch, obtained from starch- 

 producing plants, would undoubtedly be the most suitable form 

 of introducing lithium into the system of persons suffering from 

 Sfout. 



