78 AN ELUCIDATION OF 



The facility with which products differing widely in their pro- 

 perties, are formed by causes apparently inadequate, renders it ex- 

 ceedingly doubtful whether a vast number of the products of organic 

 chemistry, which threaten to overwhelm us with more new acids 

 and alkalies than there exist species in the vegetable kingdom, have 

 any real and distinct existence in the plant from which they are 

 supposed to have been extracted, or whether their formation is not 

 rather determined by the agents to the action of which they are 

 submitted, in the complicated processes of organic analysis. 



In the experiments recorded, we find gum converted into sugar, 

 merely by the action of a very dilute acid ; and, as was stated in 

 the last number of The Analyst, starch changed into sugar, by 

 the action of an exceedingly minute proportion of a substance itself 

 a vegetable product ; and that starch, merely by drying at a high 

 temperature, becomes soluble in cold water, loses its characteristic 

 property of colouring iodine ; and that it can no longer be converted 

 into sugar by the agency of sulphuric acid. Who that had obtained 

 it in this state, in the progress of a vegetable analysis, would not 

 have supposed that he had obtained a new substance f Who could 

 have conjectured its identity with starch ? 



We have seen that sugar, vinegar, oxalic acid, gum, and alcohol, 

 and many products that the limits of this paper have excluded, have 

 been obtained, from wood and starch, for commercial purposes. We 

 cannot but feel that organic chemistry is yet in its infancy, and we 

 almost fear to look forward in anticipation of the effects which fur- 

 ther discoveries may produce on the welfare of society, lest we 

 should be suspected of having rather given up the reins to our ima- 

 gination, than of being guided bv the sober inductions of reason. 



B+X. 



AN ELUCIDATION OF THE THREE BRITISH 

 TREBLINGS,— (Silvia). 



Perhaps no genus of British birds has been the subject of great- 

 er confusion than that which is the subject of the present paper. 

 This confusion, however, seems to have been caused chiefly by the 

 inattention of British authors ; for Temminck and other continental 

 writers have correctly described the three species, which are now 



