1917] Lipman-Gericke : Smelter Wastes and Barley Growth 551 



soils induced by the presence of the salts appears to the writers 

 rational and justifiable. However that may be, there can be 

 no question that even in the second and third crops on the soil 

 under examination the nitrogen content of the grain shows its 

 superiority in the case of the treated soils as against the un- 

 treated soils. . If this should prove true on soils in general, and 

 there is strong likelihood that it will, should it not offer us a 

 method for increasing the nitrogen content of our grain, a prob- 

 lem which has for some time been agitating agronomists and 

 flour producers in California? While, as has been indicated by 

 other investigators, a high nitrogen content of grain may not 

 necessarily imply a high gluten content of the flour, the latter 

 being the consummation anxiously sought, it is at least likely 

 that the generally higher nitrogen content of grain will also 

 bring with it a higher gluten content. Since, moreover, our 

 investigations indicate that small quantities of the metallic salts 

 are as effective in inducing the enrichment of grain in nitrogen 

 as the larger quantities, it is further possible that the means 

 suggested of raising the gluten content of grain may prove to 

 be a very inexpensive one. 



Absorption of Metals by Soil and Plant 



In discussing such problems as the one which forms the 

 subject here, the technical chemist will frequently ask to what 

 extent plants will absorb such metals as have been studied by 

 us. The literature on that topic is so rich in evidence tliat metals 

 are readily absorbed, and in considerable quantity, bj^ the plant 

 that we did not deem it desirable to go at length into such an 

 investigation with our harvested barley plants as a basis. We 

 did, however, make analyses of a number of plants from pots 

 receiving different treatments and also of the soils in some of 

 the pots. We are therefore in a position to answer partly on 

 the basis of our own data, the question above raised. On the 

 subject of the absorption of metals by plants, the reader is 

 referred for full and interesting discussions to Czapek,^^** 



116 Biochemie der Pflanzen, Jena, 1905. 



