1866.] 



resembling Quinine j in Animals^ 



79 



by alkalies. The substance does not lose its fluorescence when treated 

 with dilute sulphuric acid on a water-bath, nor even on the addition of a 

 dilute solution of permanganate of potash. In an alkaline solution with 

 permanganate of potash it is immediately destroyed. Quinine behaves in 

 a precisely similar way. 



Parts of the brain, kidney, liver, and heart, and the crystalline lens of a 

 human subject dead for many hours, were boiled with dilute sulphuric acid, 

 neutralized with carbonate of soda, and extracted with ether. The ethereal 

 residue, dissolved in dilute sulphuric acid, was examined by the spark of 

 the Ruhmkorf coil for fluorescence. From every part the extract fluoresced 

 distinctly but very feebly. The fluorescence closely resembled that caused 

 by a very weak solution of quinine. 



The lenses from sheep's, bullocks', pikes', eagles' eyes, gave a distinctly 

 fluorescent substance, and the extract from the sheep's liver fluoresced 

 very strongly. Cod-liver oil also fluoresced very distinctly. The so-called 

 pills of cod-liver oil gave no fluorescence. 



The fluorescent substance could be extracted by treating the finely 

 divided substance with alcohol, and the residue of the alcohol solution by 

 ether, and finally dissolving the ethereal residue in water acidulated with 

 sulphuric acid. 



It follows from these experiments that there exists in the body of man 

 and animals, fishes, and birds a substance which can be extracted from any 

 of the tissues by the same process as quinine when present can be extracted. 

 This substance has the same reactions with chemical agents as quinine has, 

 and the action of light upon this substance is almost, although not alto- 

 gether, identical with its action on quinine. 



This substance is visible in the lens of the human eye during life. It is, 

 from its mode of separation and reactions, an alkaloid bearing a close re- 

 semblance in its properties to quinine. 



For the present we shall call this animal quinoidine. It is the cause of 

 the blue fluorescence of weak acid extracts from any of the tissues of the 

 body of men and animals. When concentrated, the fluorescent substance 

 is bluish green. 



On the Fluorescent Substance produced hy treating Bile with strong Sul- 

 phuric Acid, 



We were unable to insulate and extract the substance which causes the 

 green fluorescence in bile when it is treated with strong sulphuric acid ; nor 

 could we separate that which forms in white of egg when a solution in 

 water is exposed to the air. 



The bile dissolved in strong sulphuric acid was transparent by trans- 

 mitted fight, and appeared as a brownish-yellow solution ; by reflected 

 light, even with the ordinary gaslight, it showed a strong green fluorescence, 

 in much larger quantity than, and entirely diflferent in appearance from, the 

 blue fluorescent substance of the liver. Thus it was destroyed by diluting 

 the acid with water, but returned on the addition of a larger quantity of 

 Strong sulphuric acid. 



