RESPIRATION AND OXYGEN. 63 



anaerobic respiration of these is, therefore, really identical with 

 alcoholic fermentation. The anaerobic respiration of frozen seeds 

 and seedhngs produced no alcohol, and that of a frozen stem-tip of 

 Vicia faba no amount worth noting, and hence bears no relation to 

 alcoholic fermentation. A considerable amount of alcohol was pro- 

 duced in the anaerobic respiration of hving and frozen seeds of peas 

 and castor beans and of wheat germs. The anaerobic respiration of 

 these objects is, therefore, chiefly alcohoHc fermentation, since the 

 zymase was not destroyed. With living peas an accumulation of 

 alcohol was observed only in the absence of oxygen. Frozen peas, 

 on the contrary, accumulated considerable amounts of alcohol with 

 complete access of oxygen. This is explained by the fact that the 

 oxidation processes in plant-cells are weakened in consequence of 

 killing. With both normal and anaerobic respiration of living and 

 frozen plants, acetone and various acids were formed under certain 

 conditions. 



Stoklasa, Ernest and Chocensky (1906 : 302) concluded that in 

 most cases anaerobic respiration is an enzymatic process identical 

 with alcoholic fermentation. This is true of the anaerobic respira- 

 tion of the frozen organs of seed-plants, as well as of the leaf and root 

 of the sugar-beet, and the tubers of the potato. Under anaerobic 

 conditions they isolated noticeable quantities of lactic acid from 

 sugar-beets. 



Palladin and Kostytschew (1907 : 51) studied the anaerobic res- 

 piration of etiolated plant parts and concluded that seed-plants can 

 produce alcohol only in the presence of carbohydrates. In the 

 absence of these, anaerobic respiration leads to the production of 

 CO2 without the formation of alcohol. 



Kostj^tschew (1908 : 537) assumed that the intermediate products 

 of alcohoHc fermentation are oxidized under the access of oxygen 

 and that alcohol in consequence is to be regarded as a by-product of 

 respiration which is not produced under normal conditions. He 

 further concluded (1913 : 129) that in the majority of cases the anae- 

 robic respiration of seed-plants is not identical with zymase fermen- 

 tation, since in most cases other reactions occur along with the latter. 



Stoklasa and Ernest (1908) subjected roots of Hordeum vulgare 

 and Zea mays to an atmosphere consisting of 94 per cent nitrogen 

 and 6 per cent oxygen, and roots of buckwheat to 94 per cent hydro- 

 gen and 6 per cent oxygen, and found that they secreted acetic and 

 formic acids. They concluded that these acids are formed only 

 when there is a lack of oxygen for the normal oxidation processes of 

 the root. With the proper access of oxygen, acetic and formic acids 

 are further changed in the living cell, and are finally broken up into 

 carbon dioxid and hydrogen, the latter probably being largely oxi- 

 dized to water. The roots of buckwheat, rye, oats, and corn all 

 showed formic acid in the absence of oxygen, while rye yielded acetic 



