Chemical Science, 213 



In the course of these experiments, it was remarked that mor- 

 phia, brucia, and other vegeto-alkalies, combined with corrosive 

 sublimate to form triple salts, and that narcotine and cantharadine 

 had the same property, although not considered as vegeto-alkalies. 

 Being led by this to suspect that, under the influence of corrosive 

 sublimate, they might be made to neutralize muriatic acid, a weak 

 solution of the mercurial chloride was added, drop by drop, to 

 a solution of narcotine in muriatic acid ; a pulverulent white preci- 

 pitate was formed, and the liquor, at first acid, became actually 

 neutral : thus proving the alkaline tendency of narcotine, under 

 particular circumstances. 



For want of cantharadine, the proof was not so strong j but 

 still the alkaline tendency was evident. 



On experimenting with the hydriodates of the vegeto-alkalies, 

 in conjunction with the iodide of mercury, the compounds formed 

 appeared to be very definite and constant ; and whenever a vegeto- 

 alkali combined with acetic or hydriodic acid occurs, the double 

 iodide of mercury and potassium occasions the precipitation of a 

 double salt, consisting of the iodide of mercury and the hydriodate 

 of the vegeto-alkali. This precipitate is always white in the state 

 of hydrate, but becomes yellow by heat. Generally it is uncrys- 

 tallizable, nearly insoluble in water and alcohol, and but slightly 

 sapid. The compound containing cinchoniais the only one analyzed, 

 and was found to contain, per cent., 42.67 iodide of mercury. 



Attention was then given to the double compounds formed by 

 the union of the hydriodates of the vegeto-alkali with corrosive 

 sublimate, that containing cinchonia being used. No production 

 of iodide of mercury took place, as would have happened with the 

 hydriodate of potassa : but the hydriodate and the chloride com- 

 bined together to form a stable double compound. The solutions 

 should be mixed, well agitated, and then the precipitate filtered 

 out and washed well ; it is white, but little soluble in water or 

 alcohol, uncrystallizable, and unaltered in the air: it contains 

 34.91 perchloride of mercury per cent. 



The hydriodates and hydrobromates of the vegetable alkalies 

 also combine in a similar manner with the cyanide of mercury. 

 The compounds are white, light, uncrystallizable, unaltered by 

 air, and only slightly soluble in water or alcohol : the compound 

 of the hydriodate of cinchonia contains 33.94 per cent, of cyanide 

 of mercury. — Ann. de Chimie,x\\u263. ., - 



§ III. Natural History. 



1. Method of obtaining the Skeletons of small Fishes.' — Some time 

 since I was employed in making observations on the produce of 

 some of the ponds in the neighbourhood of London, and I discovered 

 that the tadpole was a very serviceable animal in anatomizing the 

 very small fishes, as well as some of the larger sorts, generally 

 found in such places— the tadpole acting in the same manner as 



