Licence: Public Domain Mark
Credit: Physiological chemistry (Volume 1). Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![NON-NITROGENOUS ACIDS. THE BUTYRIC ACID GROUP. =CnEU03+HO. The acids of this group possess (as is indicated by the above formula) the following property; in their isolated state, that is to say when not combined with bases, they contain 4 atoms of oxygen and a multiple of a carbo-hydrogen polymeric with olefiant gas ; in their combination with bases they lose, however, 1 atom of water, so that the resulting salt con- tains an acid in which 3 atoms of oxygen are combined with a carbo- hydrogen whose hydrogen is always too little by 1 equiv. exactly to pro- duce olefiant gas with the carbon. ■ The number of this class of acids is considerable ; we have Formic acid, C2 H 03.HO=(CH), 04. Acetic acid, C4 H, 03.HO=(CH)4 04. Metacetonic acid, C6 H5 O3.H0=(CH)6 04. Butyric acid, C8 H7 03.HO=(CH)8 04. Valerianic acid C10H9 O3.HO=(CH)10O4. Caproic acid, C12Hn03.HO=(CH)1204. CEnanthylic acid, CuHi303.HO=(CH)u04. Caprylic acid, C16H1503.HO=(CH)1604. Pelargonic acid, C18Hn03.HO=(CH)1804. Capric acid, C20H19O3.HO=(CH)20O4. Closely approximating to them in their composition is another some- what extensive group of organic acids, the fatty acids, which, how- ever, we shall consider separately, because they possess certain dis- tinctive characters which would interfere with the general view which we propose to take of these acids. It is not surprising that as these acids present a perfect analogy in their composition (homology), they should also present very many simi- larities in their physical and chemical properties. They are all fluid at an ordinary temperature, and, when freed as much as possible from water, are mostly oleaginous; they do not crystallize and solidify at a higher temperature than 0°, but are so volatile that at an ordinary tem- perature they more or less powerfully irritate the eyes and nostrils; they are colorless, but have a peculiar burning or acrid taste. They are soluble in almost every proportion in water, alcohol, and ether; they redden litmus powerfully; they may be distilled without being decom- posed ; their boiling-point ascends with the number of the atoms of the carbo-hydrogen (according to Kopp, at the rate of 19° [34-2° F.] for 2 atoms of CH), and the densities of the vapors of these acids have a similar relation to the number of the atoms of the carbo-hydrogen; moreover these vapors are inflammable when too much aqueous vapor is not mixed with them. Combined with bases, these acids form salts which are for the most part soluble, and some of which crystallize readily. With organic haloid](https://iiif.wellcomecollection.org/image/b21136294_0045.jp2/full/800%2C/0/default.jpg)
