258 ROSACEiE. 



24 per cent, of tannin, and 6'25 of an acrid bitter resin, which was 

 observed by Harms (1857) to possess acid properties. 



The researches of Pavesi (1858), and still more those of BedalP 

 have made us acquainted with the active principle of the drug, which 

 has been named Koussin or Kosin. It may be obtained by mixing the 

 flowers with lime, exhausting them with alcohol and then with water ; 

 the solutions mixed, concentrated, and treated with acetic acid, deposit 

 the kosin. We are indebted to Dr. Bedall for a specimen of it, which we 

 find to consist chiefly of an amorphous, resinoid substance, from which 

 we got a few yellow crystals by means of glacial acetic acid. 



Mr. Merck favoured us with kosin prepared in his laboratory at 

 Darmstadt. It is a tasteless substance of a yellow colour, forming 

 fine crystals of the rhombic system, — readily soluble in benzol, bisulphide 

 of carbon, chloroform or ether, less freely in glacial acetic acid, and in- 

 soluble in water. We found a solution of kosin in 20 parts of chloroform 

 to be destitute of rotatory power. Of alcohol, sp. gr. 0818, 1000 parts 

 dissolve at 12° C. only 23 parts of this kosin. It is abundantly soluble 

 in alkalis, caustic or carbonated, yet has nevertheless no acid reaction, 

 and may be precipitated from these solutions by an acid without having 

 undergone any alteration. It is then however a white amorphous 

 mass, which yields the original yellow crystals by re-solution in 

 boiling alcohol, in which it dissolves readily. The analysis which we 

 have performed of kossin assigns it the formula C^^H^O^". 



Kosin fuses at 142° C, and remains after cooling an amorphous, 

 transparent yellow mass ; but if touched with alcohol, it immediately 

 assumes the form of stellate tufts of crystals. This may be repeated at 

 pleasure, kosin not being altered by cautious fusion. 



Kosin is not decomposed by boiling dilute acids. It dissolves in 

 strong sulphuric acid, giving a yellow solution which becomes turbid by 

 the addition of water, white amorphous kosin being thrown down. At 

 the same time a well-marked odour exactly like that of Locust Beans, 

 due to isobutyric acid, CH^.CH^.CH.COOH, is evolved. It would thus 

 appear that in all probability kosin is a compound ether of that acid. 

 It is very remarkable that the active principle of fern- root, the filicic 

 acid (see Rhizoma Filicis), by decomposition yields butyric acid. If 

 the sulphuric solution of kosin is allowed to stand for a week, it 

 gradually assumes a fine red; and then yields, on addition of much water, 

 an amorphous red mass which after drying is not soluble in bisulphide of 

 carbon, and may thus be purified. We have not succeeded in obtaining 

 this red derivative of kosin in a crystalline state.^ 



In its anthelmintic action, kosin is nearly allied with filicic acid.^ 



Distillation with water separates from the flowers of koso a 

 stearoptene-like oil having the odour of koso, and traces of valerianic 

 and acetic acid. No such body as the Hagenic Acid of Viale and 

 Latini (1852) could be detected by Bedall. 



Commerce — Koso is brought to England by way of Aden or Bombay ; 

 some appears also to reach Leghorn, probably carried thither direct from 

 Egypt. 



* Wittstein's Vierteljahresschrift fur ^ Fliickiger and Buri, Yearbook of Ph. 



prakt. Pharm. viiL (1859) 481; xi. (1862) 1875. 19. 



207. ^ Buchheim, Archiv der Pharmacie, SOS 



(1876) 417. 



