Appendix. 



D. 



THE AROMATIC GROUP IN THE CHEMISTRY OF 

 PLANTS. 



BY ALBERT B. PRESCOTT, 

 PROFfJS.SOH OF ORGAXrc CHEMISTRY IN THE UNIVERSITY OF MICHIGAN. 



[Read befori; the Ana Arbor ScieatiSc Association, July 3, 1875.] 



The term Aromatic Group was first given to the benzoic series 

 of compounds, as chassified around the common nucleus benzoyl, 

 by Leibig and Wohler in 1833. Benzoyl, C7H5O, was the first 

 compound radical recognized in complex vegetable products, 

 and its discovery at once opened new ways of investigation in 

 the field of organic chemistry. From time to time other chemi- 

 cal nuclei have been defined, in the construction of other 

 groups of carbon compounds, until, now, it may be said, there 

 are as many series of these bodies as most persons care to num- 

 ber among their scientific acquaintances. But there has been no 

 greater activity or keener enthusiasm or richer reward, in all the 

 labors of the forty years of organic chemistry, than in the work 

 devoted to the aromatic group. The place which this group 

 liolds in organic chemistry is similar, in certain respects, to the 

 position which organic chemistry itself occupies in general 

 chemical science. 



Among the valuable results of the labor devoted to this 

 group we must accept, first, a clearer insight into the constitu- 

 tion of molecules, throwing better light upon the chemistry of 

 all bodies. That phase of " the new chemistry" which finds 

 expression in graphic forrnulse — the theorizing as to the relations 

 of atoms to each other within the molecule, with whatever of 

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