Ointments and oleates especially in diseases of the skin / by John V. Shoemaker.

  • John Veitch Shoemaker
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Ointments and oleates especially in diseases of the skin / by John V. Shoemaker. Source: Wellcome Collection.

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    the epidermis, as well as in the sweat-ducts, but this assertion has lately been denied by Buzzi and Santi.* These earlier statements appear to have escaped the attention of physiological chemists, with the exception of Berthelot, who alludes to the probable existence in the animal body of cholesterin ethers and the fatty acids. While not belonging, in chemical composition, to the fats, cholesterin shares many of their physical properties. Crude lanolin consists of cholesterin and isocholes- terin combined with fatty acids, as stearic, and traces of others. Its odor is due to the presence of volatile fatty acids, capric and caproic. It has also been found to con¬ tain ceryl cerotate and its homologues, and, probably, cholesteiyl cerotate. A certain proportion of glycerides of the lower fatty acids is also present. The pure product should not contain these fatty acids in the free condition. Lanolin is obtained from wool-fat by a species of churning. We are not fully acquainted with the details of the improved proces-s by which it is now produced on a large scale in the chemical manufactory. The choles¬ terin fats or combinations of cholesterin with fatt}T acids do not form soaps with aqueous alkaline solutions. The free fatty acids, on the other hand, are readily saponi¬ fiable. The cholesterin fats, however, form emulsions with alkaline solutions, and also with the soaps formed from fatty acids. Such an emulsion, subjected to centrif¬ ugal action, separates into a thin milk and a cream. The cholesterin fats collect like a cream upon the top of the watery soap solution. They are freed from impurities (fatty acids or alkalies) by heating on a water-bath until melted. The resulting product is anhydrous lanolin. The substance used as a medicament contains from 25 to 30 per cent, of water, which is not, however, chemically *Monatsliefte fi\r pr^ktisclie Deraiatologie, August 15, 1889.
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