This section is from the book "Materia Medica And Therapeutics - Vegetable Kingdom", by Charles D. F. Phillips. Also available from Amazon: Materia Medica And Therapeutics: Vegetable Kingdom.
Active Ingredients. - Chamomile contains a peculiar dark-blue or dark-green essential oil, the source of its activity, and which has lately assumed an unexpected importance, from the researches of Binz and Gri-sar. The composition of the oil has been a matter of considerable dispute. Until quite of late the most generally accepted opinion was that of Gerhardt,1 who represented it as a compound of angelic aldehyde, valerianic acid, probably a small quantity of resinous matter, and a peculiar camphor-like body, C10H16, with a boiling point of 175° C., to which he gave the name of chamomilline.
More recently Demarcay2 has examined the oil, and has come to the conclusion that Gerhardt was wrong in supposing oil of chamomile to contain an aldehyde; on the contrary, he says that it is a mixture of ethers, among which the angelates and valerianates of butyl predominate. The supposed hydrocarbon, chamomilline, appears really to possess the composition of valerianate of butyl.
Physiological Action. - By far the most important physiological effect of chamomile oil is its power to lower the reflex excitability. The important paper of Binz 3 first drew attention to this property of chamomile among several other essential oils, and Grisar4 has since worked out the research with special care and very important results. His experiments were conducted on the principle introduced into practical physiology by Ttirck. This consists in suspending frogs with one limb immersed in dilute acid; the time which suffices so to irritate the limb as to cause it to be spasmodically withdrawn from the fluid, is carefully marked by a metronome, and forms the test of the degree of reflex excitability. The element of volition is got rid of by the preliminary adoption of Goltz's process - the division of the cerebral hemispheres by a knife passed through the skull in a line from one posterior orbital canthus to the other; this reduces the frog to the condition of a perfect machine for testing reflex irritability. Frogs so prepared are exposed to the acid, their degree of reflex irritability is tested by metronome beats, and then the chamomile, or other ethereal oil, is injected beneath the skin, after which successive observations are taken as the system becomes more and more impregnated with the drug. The result of experiments made in this way, and also with decapitated frogs, leaves no doubt at all that chamomile oil, even in doses that are not fatally poisonous, reduces the reflex excitability of frogs in a very marked degree. But the most important fact evolved by the researches of Grisar was that reflex excitability which has been artificially excited by strychnia or brucia can be calmed again by chamomile oil; or, rather, that an animal fortified with a dose of chamomile oil is not capable of being tetanized by a dose of strychnia which throws an unprotected frog of similar size into characteristic spasms.
1 Aon. Chim. Phys. (3) xxiv. 96. 2 Comptes Rendus, t. lxxvii. p. 360. 3 Med. Centralbl.. Feb. 8, 1873.
4 Experimentelle Beitrage zur Pharmakodynik der atherischen Oele. VonVincena Valerius Grisar. Bonn, 1873 (pamphlet).
Therapeutic Action. - Our knowledge of the medicinal virtues of chamomile has been hitherto of an entirely empirical kind, but the experiments just spoken of seem to point the way to a better understanding of the matter.
In Poisoning with Strychnia it will henceforth be a consideration whether we should not employ oil of chamomile, or some of the other ethereal oils which will be mentioned in their proper places, as antidotes. The experiment is at least well worth trying. At present we have no knowledge of the doses that might be required, but it may be mentioned that five drops of chamomile oil, subcutaneously injected, neutralized the effect of the (for a frog) very powerful dose of six milligrams (.09 grains) of strychnia.
In Cough which mainly depends on heightened reflex irritability, particularly in the kind which afflicts hysterical women, chamomile oil may take rank with valerian as a remedy of unmistakable potency; but for this purpose it must be given in sufficient doses (4 to 8 minims).
In Pulmonary Catarrh with excessive secretion and difficulty of expectoration, chamomile oil in smaller doses (2 to 4 minims) is a very useful remedy, though it has been pushed out of the field by other substances which also depend for their effectiveness upon the presence of some ethereal oil.
In the Spasmodic and Pseudo-neuralgic affections of hysterical persons, chamomile oil in sufficient doses (4 to 6 minims) is a very excellent remedy; more especially in the pseudo-angina-pectoris, and the colicky attacks to which such patients are very liable; also in hysterical pain in the fifth nerve.
In Atonic Dyspepsia, small doses (2 minims) of the oil are exceedingly useful; also in the diarrhoea of children, especially that arising from worms.
In Spasmodic Asthma, and in Whooping-cough, chamomile oil has been found by German physicians very useful. Undoubtedly the therapeutics of chamomile will now attract increased attention; and as regards
Preparations And Dose: It is important that the infusion should be discarded from use, as also the extract; and that only the oil, of first-rate quality, and presenting its original green or blue tint (which fades to yellow after a time) should be employed; the doses ranging from two to eight minims under the varying circumstances already described. Sugar is the best vehicle for the oil. (Phillips.)