Isolation of the pressor principles of putrid meat / by George Barger and G.S. Walpole.

  • George Barger
Date:
1909
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Isolation of the pressor principles of putrid meat / by George Barger and G.S. Walpole. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    that a second chloroform soluble base, which he also obtained, was probably identical with that of Abelous. Method of putrefaction and preparation of extracts. In 1906 one of us confirmed Abelous’ original observation, working on a small scale with ox hearts; in 1908, however, when we wished to isolate the bases, we found it preferable to use horse-meat and to modify Abelous’ method. The muscle was taken from a horse immediately after death, and placed in cold storage. When required, it was freed from fat and tendon, minced, placed in large bottles, each holding 10 kilos, and allowed to putrefy at 37°. The bottles Avere corked and provided with a tube to conduct offensive gases up the chimney of the incubator room. In Abelous’ experiment an equal quantity of Avater Avas added, but ave omitted this in order to avoid unnecessary evapora- tion of the extract. The meat Avas not infected Avith any particular organism, although Ave occasionally added a little material from a previous successful putrefaction. The conditions Avere in some experi- ments strictly anaerobic (carbon dioxide and mercury trap), in others only approximately so ; Ave could not trace any effect on the yield of physiologically active bases. After 6—8 days, when the mass had partly liquefied, the bottles Avere placed in a steamer and the proteins coagulated at 100° Avith hydrochloric acid (the only really unpleasant operation). After filtration in the open air the filtrate was evaporated to a thick syrup in a vacuum-pan provided Avith a sulphuric acid trap, by which means the escape of bad odours into the laboratory Avas completely obviated. Abelous and his colleagues precipitated the concentrated extract Avith absolute alcohol, but Ave found it much better to continue the evaporation further, mix the soft residue with sand and extract with acetone, Avhich is a more powerful protein precipitant than alcohol and yet a sufficiently good solvent for the hydrochlorides of the bases in question. In this Avay Ave at once obtained a much cleaner solution and we could omit the precipitation Avith mercuric chloride employed by the French chemists. After evaporation of the acetone a dark broAvn liquid remained containing a considerable quantity of fatty acids. This liquid Avas generally completely miscible with chloroform and its chloroform solution Avas extracted Avith dilute hydrochloric acid; in this Avay the bases were removed, and the fatty acids and colouring matter remained behind in the chloroform layer.
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