BY JAMKS M. i'KTKIE. 139 



plant is killed by boiling water, ether, etc., cold water 

 removes the salts. Similarly dead leaves and roots are 

 quickly deprived of their nitrates by rain. 



Nedokiitschaeff*, by growing various seedlings in Knop's 

 nutritive solution showed that when he increased the concen- 

 tration of nitrate, more accumulated in the plant ; and when 

 a certain amount was stored, no more was taken up. This 

 limit varied with different plants, and varied with the kind 

 of base, being greatest when combined with potassium. 



Towards the elucidation of the manner in which the 

 nitrogen-group enters the carbon-chain, the discovery of 

 Abelous and Aloyf is important. An enzyme has been 

 isolated from green plants, capable of reducing nitrates to 

 nitrites and ammonia, even evolving gaseous nitrogen |. 



It was shown, also, that the reduction takes place only in 

 the presence of carbohydrates. This co-relation between 

 nitrates and sugars is again brought out in the experiments 

 of Pellet^. A long beetroot was sliced and analysed. It 

 contained much sugar at the tip, the amount rapidly dimin- 

 ishing towards the crown ; and, conversely, the potassium 

 nitrates was small at the tip, and increased upwards. 



De Plata's^! experiments show that a large production of 

 sugar in plants is associated with abundance of potassium : 

 and Kritger** found that, whereas many plants feel the lack 

 of potassium very quickly, those which contain the large 

 reserves of potassium nitrate, such as the beet, continue to 

 flourish normally tfll these reserves are consumed. 



After Zaleskift and Suzukil;, there seems no doubt that, in 



• Ber. hot. Ges., 21, 1903, 421. 

 t C.R., 55, 1903, 1080. 

 X Irving and Hankinson. — Biochem. Journ., 3, 1908, 87. 

 § Bied. Cent., 1880, 235. Abst.-J.C.S. 



•^Chem. Cent., 1910, 1623. 

 ** Z. Ver. Zuckeiind., 58, 1908, 739. 

 ft Hot. Cent., 87. 

 Bui. Coll. Agrie. Tokyo, 2 and 3. 



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