426 M. Zwenger on Solanine. 



in their properties, although they are formed under similar cir- 

 cumstances from hydrochinone and saligenine, which correspond 

 to each other. 



Under the influence of various reagents — oxygen, chlorine, 

 nitric acid — arbutine undergoes a series of very interesting 

 changes, with the investigation of which Strecker is still en- 

 gaged, and the results of which will doubtless throw great light 

 on the constitution of this substance. 



Zwenger* has published a preliminary notice of an investiga- 

 tion of solanine, which has already yielded some very interesting 

 results. 



Solanine, a peculiar alkaloid found in many species of solanum, 

 is a feeble base, with scarcely any alkaline reaction, and the salts 

 of which are readily decomposed. In this respect it resembles 

 narcotine. When solanine is boiled with dilute hydrochloric or 

 sulphuric acid, the liquid becomes turbid, and crystals separate, 

 the quantity of which gradually increases. This crystalline pre- 

 cipitate is a compound of the acid used with a newly-formed 

 base, which Zwenger calls solanidine. Its salts are not vei'y 

 soluble in water ; by reciystallization from absolute alcohol they 

 may be obtained in good crystals. The alcoholic solutions of 

 salts of the base give with ammonia a gelatinous precipitate 

 of the base, which is not soluble in water, but is readily so in 

 alcohol and ether, from which it may easily be crystallized. The 

 crystals may be sublimed without decomposition. It has a 

 strongly alkaline reaction, neutralizes acids, and gives a crystal- 

 line double salt with bichloride of platinum. It imparts to sul- 

 phuric acid an intense red colour. The most unexpected part 

 of the reaction is, that the product formed at the same time is 

 grape-sugar. The solution from which the sulphate of solani- 

 dine is deposited was decomposed by baryta, and the sulphate of 

 baryta filtered oiF. The filtrate contained grape-sugar with a 

 trace of solanidine, which imparted to it a bitter taste ; but by 

 repeated evaporations to dryness and extraction with water, the 

 solanidine was got rid of, and the aqueous solution, evaporated 

 to a syrup, deposited crystals which had all the chai'acteristic 

 properties of grape-sugar. They were found to reduce oxide of 

 copper, and, mixed with yeast, underwent the alcoholic fermen- 

 tation. 



Inasmuch as, besides the new base and grape-sugar, the meta- 

 morphosis of solanine yields no other products, it must be 

 regarded as belonging to the class of glucosides — as being, in 

 fact, a hydrate of carbon copulated with solanidine. And this 

 reaction is specially interesting as affording the first instance of 



* Licbig's Annalen, February 1859. 



