ACETIC ACID WOOD VINEGAR. 337 



drunk water so acidulated and united with some base. From 

 the fact that the blood and the chyle are always alkaline, it 

 has been concluded that these acids must have united with 

 such base before being received into the blood, while it has 

 been conjectured that the bile is the source of the basic mat- 

 ter by which they are thus neutralised. This statement, which 

 does not appear to have been controverted, is in singular op- 

 position to a belief universally entertained namely, that when 

 such acids as the acetic, the citric, the tartaric, the malic, the 

 oxalic, are taken into the stomach already combined with such 

 bases as potassa and soda, they uniformly undergo decomposi- 

 tion, so that the acid is changed to a carbonate of the corres- 

 ponding base. In short, the belief of chemists of high authority 

 at present is, that if the acetate of potassa, for example, be 

 taken into the stomach, it will appear in the urine in the form 

 of carbonate of potassa ; but that if water acidulated with 

 acetic acid be drunk freely it will appear in the urine in the 

 form of acetate of potassa, or acetate of soda. These state- 

 ments, though not absolutely contradictory, are so anomalous 

 as to demand a new investigation before we can rest on 

 them with satisfaction. 



Acetic Acid, or tJie Acid of Vinegar. To acetic acid, vine- 

 gar, pyroligneous acid, sour beer, and sour wine, owe their 

 acid properties. Anhydrous or real acetic acid cannot be 

 procured wholly free from water. The formula of real acetic 

 acid as it exists in some acetates is C 4 H 3 3 , or four equiva- 

 lents of carbon to three equivalents of water. Glacial or 

 crystallisable acetic acid, the strongest that can be procured, 

 contains one equivalent of water, or is represented by C 4 with 

 the addition of four water. 



Wood Vinegar. Pyroligneous acid, or wood vinegar, called 

 also white vinegar, is obtained by the distillation of wood. 

 When pure it consists of acetic acid and water, but is by no 



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