A text-book of physiological chemistry for students of medicine / by John H. Long.

  • John Harper Long
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of physiological chemistry for students of medicine / by John H. Long. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    CHAPTER IV. THE FATS AND SUBSTANCES RELATED TO THEM. In nature we find a large number of esters composed of the fatty- acids united to glyceryl. These are the ordinary fats and as foodstuffs they are nearly as important as the carbohydrates. In structure they are practically all of the type C3H5(C»H2re_102)3, but include bodies of widely different physical properties. Some are liquids, while others at the ordinary temperature are hard solids. Nearly all vegetable products contain fats of some kind; often the amount is very small, but fre- quently it constitutes fully 50 per cent by weight of the seed, nut or fruit in question. In the animal kingdom fats are always present, in some amount, in all organisms. The animal fats are often derived from the vegetable fats consumed as food. THE NATURAL FATS. The important fatty acids combined with the radical of glycerol, C3H5(OH)3, are given in the following table. The combinations are essentially like that illustrated by this structural formula of stearin: CH2— 0-QsH350 CH _0-ClsH350 CH2 — O — C]8H350 SATURATED ACIDS, CnH2re02. Formic acid, HCHO, | Acetic acid, HC2H302 l-glycerides not natural substances. Propionic acid, HC3H502 J Butyric acid, HQH702, occurs in butter fat as glyceride. Pentoic acid, HC5H902,. valeric acid occurs as a natural compound. Caproic acid, HC6Hn02, in butter fat as glyceride. (Enanthylic acid, HC7Hi302, does not occur as glyceride. Caprylic acid, HCsH1502, as glyceride in butter and other fats. Pelargonic acid, HC9H1702, in vegetable kingdom, but not as glyceride. Capric acid, HQ„H]902, in butter and other fats as glyceride. Undecylic acid, HC„H2102, not found as natural glyceride. Laurie acid, HC12H2302, as glycerol ester in several fats. Myristic acid, HC14H2702, in nutmeg butter and other fats as glyceride. Palmitic acid, HC16H3102, as glyceride in many fats. Margaric acid, HC17H3302 obtained as artificial glyceride. Stearic acid, HCJSH3502, as glyceride in many fats. Arachidic acid, HC20H39O2, as glyceride in peanut oil. Behenic acid, HC22H4302„ as glyceride in certain oils.
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