Outlines of physiology in its relations to man / by John Gray McKendrick.

  • John Gray McKendrick
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of physiology in its relations to man / by John Gray McKendrick. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    scope, each fatty globule is seen to be siirrouiicled by a tliin nieinbrane of albuminous matter. All these substances are soluble in alkalies and in concen- trated acetic acid; they are precipitated by strong mineral acids, tannic acid, metallic salts, and by concentrated solutions of the neutral salts of the alkalies and alkaline earths. In the presence of water and of oxygen, and under the influence of a temperature of from 15° to 40° C, albuminates decom- pose into a number of products, consisting chiefly of leucine, tyrosine, ammonia, sulphuretted hydrogen, carbonic acid, and the fatty acids. 2. Albuminous Derivatives. These are substances closely related to those just de- scribed. Among them, we have the intercellular substance found in bone and connective tissue, known as gelatine or collagene, which is readily obtained from these materials by boiling. Cartilage supplies an analogous body by pro- longed boiling, called cJiondrine. In like manner, elastic tissues yield elastine] and epithelium, hair, nail, and epidermis yield keratine, which is remarkable for its richness in sulphur. A substance, in the form of colourless crystals, has been obtained from the nervous matter forming the brain and spinal cord,- and it has received the names of protagon, cerehriiie, and myeline. It has also been discovered in the red corpuscles of the blood, in yolk of egg, and in semen. Analyses of the albuminous derivatives show that gelatine and chondrine are a little richer in oxygen and a little poorer in carbon than albuminous bodies, whilst elastine contains, on the contrary, more carbon and less oxygen. Gelatine is not precipitated by any acid except tannic acid, while chon- drine is precipitated by nearly all acids. Both are soluble in water. Keratine is not dissolved by boiling water or by