Licence: Public Domain Mark
Credit: Hand-book of physiology / by W. Morrant Baker and Vincent Dormer Harris. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
882/930 (page 852)
![&c.), then with alcohol, which takes out cholesterin, fatty, and biliary acids. Hydrochloric acid is then added, which decomposes the lime salt of bilirubin and removes the lime. After extracting with alcohol and ether, the residue is dried and finally extracted with chloroform. It crystallizes of a bluish-red colour. It is allied in composition to hsematin. Biliverdin, 0, H„ N0„, is made by passing a current of air through an alkaline solution of bilirubin, and by precipitation with hydrochloric acid. It is a green pigment. BUifuacin, C(, Hjj is made by treating gall stones with ether, then with dilute acid, and e.xtracting with absolute alcohol. It is a non-crystallizable brown pigment. Biliprasin is a pigment of a greeu colour, which can be obtained from gall stones. Bilihumin (Staedeler) is a dark brown earthy-looking substance, of which the formula is unknown. Urobilin occurs in bile and in urine, and is probably identical with ■itcrcohilin, which is found in the faeces. Uroerythrin is one of the colouring matters of the urine. It is orange ]-ed, and contains iron. Melanin is a dark brown or black material containing iron, occurring in the lungs, bronchial glands, the skin, hair, and choroid. Hicmatin has been fully treated of in Chapter IV. Indican is supposed to exist in the sweat and urine. It has not however been satisfactorily isolated. Indigo, Ng 0, is formed from indican, and gives rise to the bluish colour which is occasionally met with in the sweat and urine. Indol, Cg H„ N, is found in the fteces, and is formed either by decomposition of indigo, or of the iJroteid food materials. It gives the characteristic disagreeable smell to ffeces. (4.) Nitrogenous Bodies of Uncertain Nature. Ferments are bodies which possess the proijerty of exciting chemical changes in matter with which they come in contact. Tliey are at present divided into two classes, called (i) organised, and (2) unorganised or soluble, (i,) Of the organised, yeast may be taken as an example. Its activity depends upon the vitality of the yeast cell, and disappears as soon as the cell dies, neither can any substance be obtained from the yeast by means of precipitation with alcohol or in any other way which has the j^ower of exciting the ordinary change produced by yeast. (2.) Unorgnnised or soluble ferments are tliose which are found in secretions of glands, or are produced by chemical changes in animal or vegetable cells in general; Mdien isolated they are colourless, tasteless, amoi-phous solids soluble in water and gljxerin, and precipitated front the aqueous solutions by alcohol and acetate of lead. Chemically many of these are said to contain nitrogen. Mode of action.—Without going into the theories of how these un- organised ferments act, it will suffice to mention that: (i.) Their activity does not depend upon the actual amount of the ferment present. (2.) That the activity is destroyed by high tempera- ture, and various concentrated chemical reagents, but increased by moderate heat, about 40' C, and by weak solutions of either an acid or](https://iiif.wellcomecollection.org/image/b21906300_0898.jp2/full/800%2C/0/default.jpg)
