§ 573. Effects on Man.—One of the most constant effects of santonin is a peculiar aberration of the colour-sense, first observed by Hufeland in 1806. All things seem yellow, and this may last for twenty-four hours, seldom longer. According to Rose, this apparent yellowness is often preceded by a violet hue over all objects. If the lids are closed while the “yellow sight” is present, the whole field is momentarily violet. De Martiny,[597] in a few cases, found the “yellow sight” intermit and pass into other colours, e.g., after ·3 grm. there was first the yellow perception, then giving the same individual ·6 grm., all objects seemed coloured red, after half an hour orange, and then again yellow. In another patient the effect of the drug was to give “green vision,” and in a third blue.
[597] Gaz. des Hôpit., 1860.
Hufner and Helmholtz explain this curious effect as a direct action on the nervous elements of the retina, causing them to give the perception of violet; they are first excited, then exhausted, and the eye is “violet blind.” On the other hand, it has been suggested that santonin either colours the media of the eye yellow, or that there is an increase in the pigment of the macula lutea. I, however, cannot comprehend how the two last theories will account for the intermittency and the play of colours observed in a few cases. To the affections of vision are also often added hallucinations of taste and smell; there is headache and giddiness, and in fourteen out of thirty of Rose’s observations vomiting occurred. The urinary secretion is increased. In large and fatal doses there are shivering of the body, clonic, and often tetanic convulsions; the consciousness is lost, the skin is cool, but covered with sweat, the pupils dilated, the breathing becomes stertorous, the heart’s action weak and slow, and death occurs in collapse—in the case observed by Grimm in fifteen hours, in one observed by Linstow in forty-eight hours. In those patients who have recovered, there have also been noticed convulsions and loss of consciousness. Sieveking[598] has recorded the case of a child who took ·12 grm. (1·7 grain) santonin; an eruption of nettle rash showed itself, but disappeared within an hour.
[598] Brit. Med. Journ., 1871.
§ 574. Post-mortem Appearances.—The post-mortem appearances are not characteristic.
§ 575. Separation of Santonin from the Contents of the Stomach, &c.—It is specially important to analyse the fæces, for it has been observed that some portion goes unchanged into the intestinal canal. The urine, also, of persons who have taken santonin, possesses some important peculiarities. It becomes of a peculiar yellow-green, the colour appearing soon after the ingestion of the drug, and lasting even sixty hours. The colour may be imitated, and therefore confused with that which is produced by the bile acids; a similar colour is also seen after persons have been taking rhubarb. Alkalies added to urine coloured by santonin or rhubarb strike a red colour. If the urine thus reddened is digested on zinc dust, santonin urine fades, rhubarb urine remains red. Further, if the reddened urine is precipitated by excess of milk of lime or baryta water and filtered, the filtrate from the urine reddened by rhubarb is colourless, in that reddened by santonin the colour remains. Santonin may be isolated by treating substances containing it with warm alkaline water. The water may now be acidified and shaken up with chloroform, which will dissolve out any santonin. On driving off the chloroform, the residue should be again alkalised, dissolved in water, and acidified with hydrochloric acid, and shaken up with chloroform. In this way, by operating several times, it may be obtained very pure. Santonin may be identified by its dissolving in alcoholic potash to a transitory carmine-red, but the best reaction is to dissolve it in concentrated sulphuric acid, to which a very little water has been added, to warm on the water-bath, and then to add a few drops of ferric chloride solution to the warm acid; a ring of a beautiful red colour passing into purple surrounds each drop, and after a little time, on continuing the heat, the purple passes into brown. A distinctive reaction is also the production of “iso-santonin”; this substance is produced by warming santonin on the water-bath with sulphuric acid for a few hours, and then diluting with water; iso-santonin is precipitated, and may be crystallised from boiling alcohol. Iso-santonin melts at 138°; it has the same composition as santonin. It is distinguished from santonin by giving no red colour when treated with sulphuric or phosphoric acids.