An introduction to physiology / by Augustus D. Waller.

  • Augustus Desiré Waller
Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: An introduction to physiology / by Augustus D. Waller. Source: Wellcome Collection.

    22/650 (page 4)
    The formula of the carbohydrate, dextrose, is C6H1206. All carbohydrates, in common with dextrose, contain no nitrogen, and they contain hydrogen and oxygen in proportion by volume to form water, viz. 2jlydrogen. If a carbohydrate is burned, 1 oxygen d i.e. completely oxidised, it requires additional oxygen from out- side itself only for the carbon; the amount of oxygen in the carbohydrate itself is sufficient for the complete oxidation of the hydrogen it contains. The formula of the fat, tripalmitin, is C51H9806, or C3H5,3(C1GH3102). Fats contain no nitrogen; they contain, relatively to the proportion 2;|h^ro^n, a great deal of hydrogen, very little oxygen. In tripalmitin, for instance, the proportion is 1^hydrogeI1. To be completely oxidised, fat requires outside 1 oxygen x ^ x oxygen to satisfy hydrogen as well as carbon. The formula of a proteid is given as C72H112N18022S, but this is not a true chemical formula, proteids, however pure, being of variable composition. We see, however, by this ap- proximate formula that a proteid contains nitrogen, and that the proportion between hydrogen and oxygen is greater than in starch, less than in fat, viz. ^o^ygen*' By weight the percentage composition of various proteids is CA to 154-5 Moreover, the proteid molecule holds to itself, if not within itself, small, but important, quantities of sulphur, of phosphorus, and of iron. There is sulphur in every proteid, however pure ; there is phosphorus in most; there is iron in one most important compound, hemoglobin. A proteid molecule is very large and composed of a large number of atoms of C. 0. H. N.; these may ' hold hands,' so to speak, in many different ways ; the molecule, while forming part of protoplasm, may take many shapes, may offer many kinds of opportunities for different kinds of chemical intercourse. It is to this character that the proteid molecule owes its preponde- rating importance in living matter; the molecule, while in living matter, is 1 all alive,' the seat and centre of an active commerce of atoms. The relation between proteid and protoplasm is very r6-9 rl5-2 i to nJ to 17-3 I 17