86 ORGANIC CONSTITUENTS. 



be detected by its peculiar odoiir, wliich. is rendered more obvious 

 by the application of a gentle warmth. The presence of an 

 acetate may be determined by the addition of a little sulphuric 

 acid ; the odour of the liberated acetic acid is at once rendered 

 perceptible. The addition of perchloride of ii'on to free 

 acetic acid produces hardly any visible change^ but if it be 

 added to a solution of an acetate, a deep blood-red colour is 

 produced. When acetates and free acetic acid are mixed up Avith 

 a large quantity of other animal matters, the best method of 

 proceeding is to separate the free acetic acid by distillation. 

 The residue must be evaporated, extracted several times with 

 alcohol, and the alcoholic residue mixed with a little sulphuric 

 acid, and distilled. The first distillation gives the free acetic 

 acid, the second the acetic acid in a state of combination. 

 The amount of acetic acid may be determined by saturating 

 the distilled fluids with potash, evaporating to dmiess, and 

 taking up the acetate of potash with alcohol of '833. The 

 acetate of potash obtained by the evaporation of the alcoholic 

 solution is frequently mixed with a little chloride of sodium, 

 the amount of which (if appreciable) may be determined by 

 nitrate of silver. 



At a red heat the combinations of acetic acid with non- 

 volatile bases are converted into carbonates. 



END OF INTRODUCTION. 



