ANALYSIS OF THE VEGETATION OF THE GRAMINE^. 591 



azote of the air, and their discovery would immensely extend our means 

 of fertilizing the earth. The pi-ocesses of investigation that I have here 

 applied to products formed by living vegetables would be serviceable 

 in these useful researches by manifesting in numerous instances, by sen- 

 sible physical characters, the existence of the principles which have 

 been introduced into tliem. 



When the annual circle of vegetation has been completed I shall col- 

 lect into a single memoir the results that have thus been obtained, ac- 

 companied by a detail of the experiments which have been employed to 

 determine them. This collection of examples, added to my previous 

 researches and to those which I have pursued in conjunction with M. 

 Persoz, will be sufficient to show in what manner indications of circu- 

 lar polarization may be rendered subservient to organic chemistry and 

 also the manner of applying them to that purpose. The only task that 

 I proposed for my own performance will then be accomplished, and I 

 shall expect from the active dexterity of our chemists the almost unli- 

 mited developments which it appears to promise. 



Examination of an Optical Character, by which, according to 

 M. Biot, Ve(jetahle Juices capable of producing Sugar 

 analogous to Cane Sugar, and those capable only of pro- 

 ducing Sugar similar to Grape Sugar, may be immediately 

 distinguished ; by M. Chevreul. 



From the Nouvelles Aimales du Museum d'llistoire NatureUe,\'o\ ill. p. 307, sq. 



!• X HAVE judged it expedient to devote a special memoir to the 

 development of the reasons upon which the opinion expressed in the 

 preceding report [on several papers relative to the chemical and physio- 

 logical history of starch,] respecting the importance of the optical cha- 

 racter proposed by M. Biot to be applied to organic chemistry reposes; 

 in order to show that this opinion has not been formed without due 

 consideration, and that it is in fact only an application of the views 

 which I have elsewhere explained long ago, upon the relative impor- 

 tance of the various properties suitable to be employed as characters 

 in the definition of chemical species, considered individually and col- 

 lectively. 



2. To attain this object I proceed to examine the optical character 

 proposed by M. Biot : 



F^irst, in relation to the objections which may be urged against its 

 importance in organic analysis, and in the definition of species. 



