Treatise on human physiology : For the use of students & practitioners of medicine / By Henry C. Chapman. Illustrated with 595 engravings.

  • Chapman, Henry C. (Henry Cadwalader), 1845-1909.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Treatise on human physiology : For the use of students & practitioners of medicine / By Henry C. Chapman. Illustrated with 595 engravings. 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.

    59/934 (page 53)
    In the case of olein, C,H^(C,,H3,0,),, and palmitin, C,H^(C,,H3P,),, the three atoms of hydrogen in glycerin are repkiced by the residues of three molecules of oleic acidjCj^Hg^.,, and palmitic acid, CjgH3202. Such being the constitution, chemically, of neutral fats, it be- comes intelligible why stearin, for example, in the presence of vapor of water heated to 572° F., takes up water, and splits into glycerin and stearic acid, as follows : Tristearin. Water. Glvcerin. Stearic acid. The action of alkali, soda, for example, upon stearin, is another example of this process, the stearin splitting up into glycerin and stearic acid, the latter combining with the sodium to form sodium stearate or soap, as follows : stearin. Soda. Glycerin. Sodium stearate. 2(C,,H^,„0J + 6NaOH = 2(C3H^03) + GXaC^^H^^^ Saponification, as the splitting of a neutral fat into glycerin and fatty acid is called, whether alkali be present or absent, is brought about in the system by tlie action of the steapsin of the pancreatic juice upon fat. It is a most important function, since the neutral fat is emulsified by the soap so formed, that is, subdivided into mi- nute particles, thereby rendering it absorbable. In a similar man- ner oleic acid, sodium oleate, and other fatty acids and soaps are formed in the system. The odor of the axilla and feet is probably due to the presence of fatty acids. It is an interesting fact that, after feeding an animal with a fatty acid, the chyle will be found to contain a considerable amount of neutral fat, showing that a syn- thesis the reverse of saponification takes place, that is to say, the fatty acid, fed combines with the glycerin of the body, three mole- cules of water being lost to form neutral flit.^ In this connection it may be mentioned that there are other monatomic, monobasic, fatty acids occurring in the body, to be referred to hereafter, such as formic, propionic, butyric, and caproic acids. iMunk, Yirchow Archiv, 1880, Bd. 80, _s._17. 2 A monatomic acid is so called because it is derived from a monatomic alcohol. Acetic acid (C'.^H^O.,), for example, being derived from alcohol (C.JIgO) among other wavs bv oxidation, as follows : Alcohol. Oxygen. Acetic acid. Water. C^HgO 4- 0, = C^HA + H.,0 Acetic acid is a monobasic acid, one atom of hydrogen being replaceable by a monad element, as in the formation of potassium acetate, according to the following reac- tion : Acetic acid. Pota.ssic hydrate. Potassium acetate. Water. C2H,02 + KOH •= KC^HjO., + H,0 What has just been said of acetic acid is applicable to the remaining fatty acids, they all having the constitution chemically of a hydrocarbon group tinited with COoII.