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Relation of the Chemical Constitution of Bodies to Taste. 197 



* 



The taste is, therefore, not dependent upon any one of the ele- 

 ments present, since each may be replaced entirely by another 

 without destroying the taste. 



In the coniniunication submitted to the American Academy, 

 attention was directed to the common formula, in which, accord- 

 ing to Davy and to most modern chemists, all the acids contain- 

 ing hydroo;en may be written, and also the oxygen acids which 

 ordinarily exist in combination with an atom of water, as sul- 

 phuric and nitric acids; to wit, H + x ; in which x represents all 

 that part of the acid not replaced by metal in neutralization, A 

 few examples follow : 



H + Cl = Hydrochloric acid. H-f-NOe z=: Nitric acid. 



H -f I = Hydriodic '' H -f C2HO4 = Formic 



H4.Br =Hydrobromic '' H']-C20^ .^Oxalic 



H4-F = Hydrofluoric " H-I-C4II3O4 = Acetic 



H -j- Cy zn Hydrocyanic *' H4-C6FI5O4 ^i: Metacelonic acid. 



H -{^ SO3 = Sulphurous " H 4- C8H7O4 =: Butyric 



H-fS04 = Sulphuric " H -j-CioHi 1O4 = Valerianic " &c. 



The iuquiry naturally arises, have sour bodies a common form ? 

 to which, and not to the nature of the constituent particles, the 

 property of sourness is to be attributed. They (the acids) are 

 composed of one larger atom, or group of atoms united to the 

 least atom, hydrogen, easily replaceable by a metal, and bound to 

 the group by an affinity apparently much feebler than that of any 

 of the remaining elements. 



An allusion was made, in the communication to the Academy, 

 to the class of resins — some of the soluble members of which 

 possessing a bitter taste — might, according to a research of Heldt 

 i^pon Santonine, be referred to a single fundamental type. He 

 refers the resins, for their origin, to the oxydation of the essen- 

 tial oils, and though the conception has been entertained by 

 other chemists, it has first met with a full exposition in this pa- 

 per. The hydrogen of essential oilsoxydates, as a general thing, 

 much more readily than the carbon. The following formulas 

 present Heldt's view of the production of resins. All are de- 

 rived, he conceives, from Ci oHe, 



CioH8]"-Hx-l-Ox=:R, 



CioH8]"-HxH-Ox-f(HO)yr=R. 



"CioH8J"-Hx-{-Ox-j-Oy=R. 

 rCioH8]n-Hx+Ox-{-Oy=[HOJz=R. 



[CloH8jn+[HO]x=R. 



These formulas present in the original essential oils, groups of 

 atoms, in which a part of the hydrogen occupies a more exposed 

 situation, if one may employ the illustration, than other parts of 

 the molecule, and oxydates more readily. In this respect there 

 is approximation to a common form, in view of which the in- 



