METABOLIC PROCESSES IN THE PLANT. 



285 



in the apparatus for three to four weeks, we open it, pound the 

 material, and subject it (in the case of the seedlings after addition 

 of water) to distillation. The fruits yield perhaps H per cent, 

 (in terms of the weight of fresh material taken), the pea seedlings 

 .5 per cent, of their dry weight of alcohol. The alcohol can easily 

 be recognised as such in the manner above indicated. Aromatic 

 compounds and fusel oil are always mixed in larger or smaller 

 quantities with the alcohol produced.* 



Yeast, as shown particularly by Pasteur's valuable researches, 

 is able to grow not only in presence of air, but also, though more 

 slowly, in complete absence of Oxygen. On the other hand, tin; 

 Hntyric acid organism (Clostridium butyricum, a Schizomycete) 

 is one of the obligate aiiaerobia. The fungus appears in the form 



FIG. 105. Apparatus for proving that there are organisms capable of growing in com- 

 plete absence of Oxygen. 



of shorter and longer rodlets. We prepare a 5 per cent, solution 

 of cane-sugar, to which we add some meat extract, so that the 

 fluid appears yellowish. We also add to the fluid some Potassium 

 carbonate, so as to give it a slightly alkaline reaction. Still more 

 suitable is the following food solution : to one litre of water 

 ~>0 gr. of potato starch, O5 gr. of Ammonium chloride, O2 gr. of 

 Magnesium sulphate, 1 gr. of acid Potassium phosphate, and 25 gr. 

 of chalk. If the solutions are left in the thermostat at 35 C., in 

 not too tightly corked thick- walled vessels, they exhibit by the 



''' The formation of alcohol, according to our present views, appears to be 

 actually a function of the living protoplasm. The whole subject, however, 

 needs further very searching experimental treatment. We must particularly 

 keep in view the injuries which plant-cells experience when kept for a consider- 

 able time in a space devoid of Oxygen. 



