APPENDIX TO CHAPTER IV. 



HISTORY OP GEINE. 



Some account of the chemical history of a substance which 

 has caused no little discussion in late agricultural reports 

 and publications, may not be here misplaced. It may tend 

 to soften the doubts of those who are, and with reason apt 

 to mistrust the utility of a substance, upon whose chemical 

 nature there is such an apparent difference of opinion. If 

 farmers are to wait till doctors agree, there will be no har- 

 vest. Happily this discussion is in nowise connected with 

 the practical application of geine. It is a difference about 

 names, not things. In 1797, Vauquelin, a distinguished 

 French chemist, gave an account of a substance which had 

 exuded from the bark of an elm tree. It was a shining, 

 brittle, black substance, insoluble in alcohol, soluble in hot 

 water, with a brown color, and contained potash. 



In 1802, Klaproth, a Swedish analyst, received from 

 Palermo a specimen of this elm gum, and found it con- 

 tained a portion of resinous matter, and confirmed Vauque- 

 lin's observations. In 1810, Berzelius, the most acute 

 chemist of the age, in experimenting on the barks of various 

 trees, noticed products similar to the elm gum, particularly 

 in pine bark, Peruvian bark, and especially in the elm, 

 whose properties will be presently mentioned ; but he not 

 only gave these products no name, but pointed out marked 

 differences between them. The substance found in pine is 



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