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The inorganic poisons were first excluded by the negative 

 results obtained when the usual reagents and tests were 

 applied for mineral poisons. But on extending the investi- 

 gation to organic radicals a comparatively large quantity of 

 the alkaloid solanine was found. This substance is found 

 in several species of the genus Solarium, (S. dulcamara, S. 

 nigrum, S. tuberosum, &c.) in S dulcamara it exists in the 

 berries and whole plant, in S. tuberosum it is found in the 

 berries, but more especially in the sprouts formed in warm 

 and moist cellars. Traces of it are always found in the tuber, 

 as may readily be ascertained by the peculiar scratching 

 sensation produced at the root of the tongue on tasting some 

 of the raw potato. But it seldom amounts to more than 

 one part in two thousand, and exercises little or no deleterious 

 influence, as boiling water extracts the greater part of it. 

 The specimens examined by me, however, contain a much 

 larger quantity ; about one part in ten thousand. There 

 exists no doubt that the mischief produced by the use of the 

 potato is due entirely to the solanine, for it is a very violent 

 poison and requires but a very small quantity to produce 

 symptoms of ill health when taken by a human being as I 

 ascertained by a direct trial. I extracted the solanine from 

 eighteen ounces of potatoes, on administering one tenth of 

 the quantity obtained or perhaps one fifth of a grain to my- 

 self, it produced stupor, lassitude and general symptoms of 

 of deranged health. 



The method of extracting solanine is as follows ; the po- 

 tatoes, after being cut in small peices or crushed with a ham- 

 mer, are treated with water made acid, with sulphuric acid, 

 in a porcelain or glass vessel, which is allowed to remain for 

 twenty four hours. The sulphuric acid unites with the 

 alkaloid and forms a soluble compound, solanine itself not 

 being very soluble in water. It is then filtered through cloth, 

 and the fluid extract treated to coagulate the albuminous 

 matter, allowed to stand for some time that all solid particles 

 may subside, then filtered through paper. The solanine, 

 being very little soluble in water, is cast down from its com- 

 bination with sulphuric acid by the addition of caustic am- 

 monia to the extract, this being allowed to stand for a short 

 time, is again filtered throught paper, when all the solanine 

 with some other organic matter will be on the filter. This 

 is carefully washed with water containing a large quantity of 

 caustic ammonia, which removes nearly all the coloring 



