This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
Alcohols of the Series C2H2n+1OH. - These may be regarded as hydrates of the radicals. They differ from the hydrides by the radical being united in them to hydroxyl, HO, instead of to hydrogen. The most important of them are :Methyl alcohol, CH4O. Wood spirit.
Ethyl alcohol, C2H6O. Spirit of wine.
Propyl alcohol. C3H8O.
Amyl alcohol, C5H12O. Fusel oil or potato spirit.
General Action. - These alcohols have all a toxic action when given in sufficiently large doses. The general effect they produce on the organism appears to be much the same in all, viz. paralysis affecting the nerve-centres in the inverse order of their development. Their lethal power and the symptoms they produce are modified by their physical characters, such as their solubility in water, and their volatility; for if they are not readily soluble in water they cannot be readily absorbed, and probably will not be readily excreted. Their toxic power increases with their atomic weight, so that a less quantity of the higher alcohols will produce death. This is shown in the following table by Dujardin-Beaumetz. It will be noticed, however, that the lowest term and also the higher terms of the series form exceptions. This may possibly be due to rapid absorption as compared with excretion (p. 39) in the case of methylic alcohol, and to slow absorption in the case of cenanthic and caprylic alcohols : -
Kind of Alcohol
Mean toxic dose in grammes per kilogramme weight of the animal
Methylic Alcohol, CH4O
. . .
Fermented . -
Ethylic „ C2H6O
Propylic „ C3H8O
(Isopropylic) „ (C3H9O)
. . .
(3.7 to 3.8)
Butylic „ C4H10O
Amylic „ C5H12O
(Enanthic „ C7H16O
. . .
Caprylic „ C8H18O
7 to 7.5
. . .
All the alcohols produce symptoms which are divided by Dujardin-Beaumetz into three stages, the first of which corresponds to the first and second stages of action I have given at p. 206, and his second and third corresponding to the third and fourth of mine respectively. These stages are modified by (a) the kind of alcohol used, (b) its quantity, and (c) the resistance of the subjects.
Ethylic alcohol has the most typical action, and in poisoning by it all the stages succeed one another in regular order. In the case of the other alcohols obtained by fermentation the stages are also regular, but the farther the alcohol is from ethylic, the less regular do the stages become. They succeed one another more rapidly, their character is less marked, and convulsive phenomena appear.
In the case of methylic alcohol, the excitement is greater, the subsequent stages succeed one another more quickly, and reach their acme sooner; but if the dose be insufficient to cause death, the effects pass off more quickly.
In the case of cenanthic and caprylic alcohol, the stages do not present the same regularity, and convulsions occur.
All the alcohols now mentioned lower the temperature.
On post-mortem examination after acute poisoning by alcohols, the blood, stomach, intestines, liver, lungs, and kidneys are found to be affected. It is possible, however, that some of these lesions are not to be regarded as specific consequences of the action of alcohol, but rather as due to the death by asphyxia which ensues from the respiratory paralysis. The blood is of a dark colour, and forms clots in the heart. "When the alcohol is given by the mouth, the stomach and intestine are much congested and softened, the congestion being greater when the alcohol is undiluted. When the alcohol is injected sub-cutaneously, the stomach is little altered, but the intestine is congested, the congestion being probably due, according to Dujardin-Beaumetz, to elimination of the alcohol by the intestinal mucous membrane. The liver is the gland most affected. It is congested, soft, and friable. The spleen is also gorged with blood, and soft. The lungs are congested with small extravasations, which are most abundant when the alcohol has been given by the mouth. Haemorrhages are observed in the kidneys, especially in the case of the non-fermented alcohols.
Characters. - A colourless, mobile liquid. When pure it has a taste and smell somewhat like ethyl alcohol; but ordinary wood spirit contains many impurities which give it a disagreeable odour and burning taste.
Preparations. - By destructive distillation of wood, and neutralisation and repeated distillation of the product.
Uses. - The admixture of wood spirit with alcohol renders the latter so disagreeable as to unfit it for drinking, so that it can be sold under the name of methylated spirit as a solvent and for other uses in the arts, without interfering with the duties on potable alcoholic drinks.
Alcohol Ethylicum, B.P. C2H5OH. Ethyl Alcohol. Absolute Alcohol.
Characters. - Colourless and free from empyreumatic odour. Sp. gr. 0.797 to 0.800. Containing 1 to 2 per cent. of water, B.P.
The solutions of maltose which yield alcohol are generally prepared from malt. This is made by steeping barley for a while in water till it begins to germinate. The barley when fresh contains starch and a ferment termed diastase, which converts the starch into maltose during the process of germination.
When this has gone far enough, as is ascertained by the radicle attaining a certain length, the process is stopped by roasting the malt, as the sugar would all be used up again by the plant if it were allowed to continue its growth. The malt is then infused in warm water, and the solution of maltose which it yields is fermented by yeast, a small fungus which causes the sugar to split up and yield alcohol. The alcohol thus obtained is very much diluted with water, and in order to separate them the liquor is distilled, when the alcohol passes over first, and the greater part of the water is left behind.
Reactions. - Entirely volatilised by heat. Not rendered turbid by mixing with water, and does not cause anhydrous sulphate of copper to become decidedly blue on shaking.