THE VITAMINES IN THE VEGETABLE KINGDOM 65 



that in the course of this work, the firmly established physical and 

 chemical characteristics of the active substances are best in accord 

 with the conception of a second vitamine. 1 Working with Oidium 

 lactis, Linossier (170a) found that on addition of vitamine, the 

 activation took place only in the first few days. 



HIGHER PLANTS 



In the first edition of this book, in anticipation of a possible 

 analogy to animal growth, we wrote a small chapter on plant 

 growth without being able to find any supporting experimental 

 evidence; still, it was not necessary to wait for it a long time. In 

 1909, Clinton (171) made the observation that plant extracts have 

 the power to stimulate the reproduction of certain plants. Haber- 

 landt (172) found that parts of potatoes containing the morphological 

 structure, "Leptom," showed cell division when placed in a nutritive 

 solution. The embryonic structure only was able to undergo cell 

 division without the presence of leptom. This author suspected the 

 presence of a special hormone in leptom corresponding to the internal 

 secretions of animals. 



Bottomley (173) was the first investigator to take up this problem 

 seriously. In 1912, he occupied himself with the problem of the 

 ability of certain bacteria to transform the humic acids of peat into 

 water-soluble combinations. He demonstrated at that time that 

 such peat contains all of the chemical combinations necessary for the 

 growth of young tomato plants, buckwheat, radishes, and barley. 

 In the further development of this question, which appeared at 

 about the same time as our earlier vitamine work, Bottomley (174) 

 extracted a substance from bacterized peat with water or alcohol. 

 The addition of phosphotungstic acid to this alcoholic extract yielded 

 a precipitate which, upon decomposition, acted favorably on plant 

 growth. The solution thus obtained was precipitated with silver 

 nitrate, and in the end the growth substance was found present in 

 the same fraction as the vitamine. All active fractions were tested 

 for their influence on the growth of young plants, and then, in order 

 to set forth the results more clearly, the cotyledons, which contain 



1 Willaman defines the vitamines as a class of substances whose presence 

 is necessary for normal metabolism, but which do not contribute to the 

 requirements of the organism as regards inorganic constituents, nitrogenous 

 substances, and energy producing food constituents. 



