68 



THE VITAMINES 



The extracts of the fermented peat were examined chemically by 

 Rosenheim (ISO). 2 To give the reader some conception of the 

 quantities of the active substances used, we shall go into these experi- 

 ments more in detail: 15 grams of bacterized peat were extracted 

 with 2 liters of water and 500 cc. of this brown solution were diluted 

 to 1250 cc. This extract contained 0.045 per cent of dry substance, 

 0.034 per cent of organic and 0.011 per cent of inorganic material, 

 and 0.003 per cent of nitrogen. The plants investigated (Primula 

 malacoides) received in one dose 0.18 grams of peat, which contained 

 20 mgm. of organic material and 1.9 mgm. of nitrogen. The plants 

 so treated (figure 5) grew higher, showed leaves of a deep green color, 

 and were also generally larger than the controls, which is especially 

 apparent in the illustration. The substance which could bring about 



such a great change must belong to the type of vitamines, according 

 to Rosenheim. From the active extract, it was possible to obtain 

 with phosphotungstic acid a precipitate which was only partly 

 soluble in acetone (like the vitamines, as we shall see later). Rosen- 

 heim hoped to extend his experiments to include yeast and milk. 



Bottomley (181) investigated the nitrogenous constituents of the 

 peat, and although there was no nucleic acid present, he did find 

 their decomposition products, an uracil-adenine-dinucleotidc and the 

 components of guanine-cytosine-dinucleotide. 



Appleman (182) believed that potato tubers contained substances 

 which were necessary for the growth of the shoots. It is therefore 

 of importance in planting potatoes, that not too small a piece of the 



2 In this paper, Rosenheim claims priority as to the findings on the impor- 

 tance of vitamines for plants. 



