SYNTHETICAL RESEARCHES ON ACIDS OF THE LACTIC SERIES. 341 



duction of caproic acid, as above described, shows that the action of these substances 

 upon each other is susceptible of yet a fourth modification, in which the molecule of 

 amylic oxalate appears to divide into its two constituent atoms of amyloxatyl (C O Ayo), 

 which then unite with amyl to form amylic caproate. 



(CO Ayo ^ ^ 2 C Ay O Ayo, or 2^ ^^^^2. 



(COAyo ^ ^^ ^ / ' (COAyo 



Amylic oxalate. Amyl. Amylic caproate. 



The source of the amyl in this reaction is not difficult to discover; for, as above stated, 

 torrents of the usual products of its transformation (amylic hydride and amylene) were 

 evolved during the operation ; in fact it was obvious that no inconsiderable portions of 

 the zinc and amylic iodide were occupied in the formation of zincic iodide and amyl, a 

 considerable proportion of the latter being as usual transformed at the moment of sepa- 

 ration into amylic hydride and amylene. 



2AyI+Zn"=Zn"l2+Ay2. 



Meeting with this reaction, as we have done, only at the close of the above investiga- 

 tion, we have not been able to ascertain whether or not it is one of general occurrence. 

 It is true that we have not observed the formation of the fatty ethers in any of the 

 foregoing reactions in which zinc and the iodides of the radicals were employed ; but 

 the comparatively low boiling-points of these ethers might easily have led to their 

 having been overlooked. We consider, however, this reaction of so much importance, 

 that we shall at once endeavour to ascertain whether or not it occurs in the other 

 homologous cases, giving rise to acetic ether in the case of methylic iodide, and to pro- 

 pionic ether where ethylic iodide is employed. 



We have already stated that the constitution of the acids of the lactic series has 

 been the subject of fruitful controversy amongst chemists. In this discussion widely 

 different opinions have been advanced : some have assigned to lactic acid the formula 

 (CgHigOg), and attributed to it a dibasic character; some have reduced this formula to 

 C3 Hg O3, still retaining for the acid the same degree of basicity ; whilst others, again, 

 have regarded it as monobasic, and assigned to it the lower formula. This contro- 

 versy respecting the constitution of an acid so intimately related to several of the most 

 important families of organic compounds, has been the incentive to numerous and highly 

 important researches, which have thrown valuable light not merely upon the structure 

 of the lactic series itself, but also upon that of organic families allied with this series. 



Amongst the experimental investigations which have contributed to the elucida- 

 tion of this subject, we beg leave to refer to those of Wurtz *, ULKicnf, Stbecker;}:, 

 Bruning§, Perkin, and Duppa ||. Again, Wurtz, PerkixV, Kekul^, and especially 

 KoLBE, have, by their acute theoretical speculations, most ably supplemented direct 

 investigation. 



* Comptes Eendus, vol. lii. p. 1067. + Ann. dor Chcm. und Pharm. vol. xci. p. 352. 



t Ann. der Chem. und Pharm. vol. cix. p. 271. § Ibid. vol. civ. p. 191. || Ibid, vol. cviii. p. 113. 



MDCCCLXVI. 3 A 



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