Physiological chemistry (Volume 2).

  • Lehmann, Karl Gotthelf, 1812-1863.
Date:
1855
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Licence: Public Domain Mark

Credit: Physiological chemistry (Volume 2). 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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    intercellular fluid; and on this account the scrum of the chyle is in general clearer than the original chyle, although it always retains some degree of turbidity, or at all events of opalescence. In the serum of the chyle albumen is also the preponderating solid constituent. This albumen has been regarded as imperfectly developed (Prout), owing to the circumstance that it coagulates on being heated, and is at the same time precipitated to a certain degree by acetic acid. Independently of the illogical character of the argument which can assume the existence of a chemically imperfect substance,—and we might just as rationally assume that malaria is a more perfect carburetted hydrogen than olefiant gas, or the reverse,—every one who has read the observations in page 296 of vol. i. must at once conclude that the only difference presented by the albumen arises from its being combined with more alkali in the chyle than in normal blood; and this, moreover, is confirmed by direct investigation, at least in the chyle of the thoracic duct of horses. The chyle-serum is not rendered turbid by strong dilu- tion with water ; when boiled, it does not so much form coherent flakes as a milk-white, opaque fluid ; and it becomes covered on evaporation by a colorless membrane. The aqueous extract of the residue of the chyle exhibits a strongly alkaline reaction, and the solution may be rendered turbid by neutralizing it with acetic acid. After this turbidity has been removed by a more copious addition of acetic acid, ferrocyanide of potas- sium gives rise to a considerable precipitate. The aqueous extract of the residue of the chyle presents great turbidity on being boiled with hydrochlorate of ammonia, as well as on the addition of nitric acid. The albumen, after being thoroughly washed with water, alcohol, and ether, was found to yield on incineration 2*0680 of mineral constituents, in- cluding a considerable amount of alkaline salts, which effervesced on the addition of acids. The supposed presence of casein in the chyle, instead of being proved, seems therefore to be rendered very improbable. It would be an important point if we could show that the peptones of the albuminous substances in the food are present in the chyle, but from our ignorance of the necessary reagents, this question cannot at present be decided by direct investigation. As the chyle contains from 2-5 to 3*00 of non-coagulable substances which are only soluble in water, and consists of a large proportion of albuminate of soda and mineral salts, it is at all events improbable, to say the least, that peptones should be present in the chyle discharged from the thoracic duct of the horse ; and hence the question, whether the peptones are elaborated in the mesen- teric glands into albumen and fibrin, still continues wholly undecided. Our microscopical and microscopico-chemical investigations prove that fat is contained in large quantity in the chyle, and even show with some degree of probability that the chyle contains a considerable quantity of non-saponified fat in the smaller lacteals, whilst in the thoracic duct the proportion of saponified fat preponderates. I was unable by any method to obtain a crystallizable fat from the saponified or non-saponified fats of the chyle of the horse; and other observers have stated that they could only discover a greasy and tallow-like fat, although they may not always have attempted to detect the fat-crystals by the aid of the micro- scope.