396 Foreign and Miscellaneous Intelligence. 



this menstruum, when cold, than when warm, and much less than the 

 oil. The latter portion may be entirely separated by the addition of 

 a little lime to the warm solution of piperin with the oil, and leaving 

 it to crystallize in the same vase ; the piperin, when cold, may be 

 separated at leisure : by re-dissolving the crystals thus procured, 

 adding a little animal charcoal, and filtering when hot, a solution 

 will be obtained, which, upon cooling, will afford crystals of a canary 

 white, regular and free from acridity. Mr. Pontel has advised the use 

 of caustic potash, and the effect is certainly very marked. The 

 solution should be weak, for caustic potash has a tendency to alter 

 the nature of the substance, and instead of procuring piperin, I once 

 formed a compound that very much resembled soap, and all subse- 



?uent attempts to procure the substance in crystals failed ; moreover, 

 have always observed, that those crystals obtained by the aid of 

 potassa had more or less of a reddish tinge, and were very brittle. 

 Piperin, when pure, crystallizes in right square prisms, occasionally 

 presenting an anomaly, the crystals, particularly those obtained 

 through the means of potassa, being hollow, or containing an interior 

 decrement, the four vertical sides being entire, and showing the form 

 of the crystal ; they are insoluble in water, soluble in cold alcohol, 

 and more so when warm ; insoluble in acetic or other acids. Piperin 

 has been employed latterly in Italy as a febrifuge*. 



25. ON SALICINE BY MM. PELOUZE AND JULES GAY LUSSAC. 



Salicine, when pure, forms white crystalline prismatic needles. It 

 has a bitter taste and somewhat of the odour of willow bark. One 

 hundred parts of water dissolve 5.6 parts of salicine at 67 F. : at 

 212 F. it appears to dissolve in any proportion. It is equally soluble 

 in alcohol, but ether and oil of turpentine take up no portion of it. 

 Concentrated sulphuric acid gives it a fine red colour, like that of 

 bichromate of potassa. Muriatic and nitric acids dissolve it without 

 producing any colour. It is not precipitated from its solution by 

 infusion of nut-galls, gelatine, neutral or subacetate of lead, alum, or 

 emetic tartar. It does not saturate lime-water when boiled with it 

 in excess : it does not dissolve oxide of lead : it fuses a little above 

 212 F., losing no water, and crystallizes upon cooling. If the heat 

 be rather higher, it acquires a lemon-yellow colour, and becomes, 

 when cold, brittle as resin. 



Salicine, burnt by means of oxide of copper, yields a gas entirely 

 absorbable by potash. The mean of two analyses gave the following 

 as its composition : 



Carbon . . 55.491 = 2.028 proportions. 

 Hydrogen . 8.184 = 2.004 

 Oxygen . . 36.325 = 1.000 



Its composition may, therefore, be represented by two volumes of 

 olefiant gas, and one volume of oxygen f. 



* Sillhimu's Jour, xviii. p. 253. f Ann, de Chimie, xliv. p. 220. 



