238 



Prof. W. B. Bottomley. 



organic substances are, without doubt, essential for the proper nutrition of 

 growing animals." 



Very little is known as to the nature and composition of these substances. 

 Unfortunately, the active substance appears to be largely destroyed by 

 chemical manipulations, and it is difficult to obtain sufficient to study its 

 chemical constitution and properties. Funk,* by a complex fractionation 

 of the phosphotungstic precipitate of anti-beri-beri substance, succeeded in 

 isolating a substance, melting at 233° C, which in amounts of O02 to 

 - 04 grm. cured polyneuritis in pigeons. This substance he considered to 

 be of the nature of a pyrimidine base. Hopkins, bowever, states that the 

 additions in his growth experiments were free from amino-aeids, purine and 

 pyrimidine bases. It is possible that these substances belong to a new group 

 of nitrogenous compounds, which exist only in small amounts in food 

 materials, but are so extremely active that minute quantities are sufficient to 

 supply the needs of the organism. 



Although these substances have been found to occur chiefly in plants, there 

 is no record of any investigations concerning the part, if any, they play in 

 the metabolism of the plant itself. 



During the summer of last year (1913) a number of experiments were 

 made at the Royal Gardens, Kew, on a series of plants, to test the 

 manurial value of Sphagnum peat which had been incubated with a mixed 

 culture of aerobic soil organisms for a fortnight at a temperature of 26° C. 

 It had been discovered that by this bacterial treatment the humic acid 

 in the peat is converted into soluble humates, and this bacterised 

 peat, after sterilisation, forms an excellent medium for the growth and 

 distribution of nitrogen-fixing organisms. As the experiments progressed 

 it was evident that, in addition to the ordinary plant-food constituents, 

 there was present in the bacterised peat a substance which stimulated 

 growth in a remarkable manner. Further experiments showed that this 

 substance was soluble in water, and was effective in very small quantities. 

 Dr. Eosenheim, of King's College, found that seedlings of Primula 

 malacoides potted up in loam, leaf-mould and sand, and treated twice with 

 a water extract of only - 18 grm. of bacterised peat, were, after six weeks' 

 growth, double the size of similar untreated plants, and it was noted that 

 flower production and root development were promoted equally with increase 

 of foliage. 



These results suggested that the growth-stimulating action of the 

 bacterised peat might be due to the presence of a substance or substances 

 similar in nature to the accessory food bodies concerned in animal nutrition. 

 * C. Funk, 1 Journ. Physiol.,' vol. 45 (1912-1913). 



