l4S On the Virtue<; and Frinciples 



of vinegar : he even thought that the existence of it might 

 be ascribed to the practice adopted by those who collect 

 cantharidcs, of exposing them to the vapour of that acid ; 

 but having subjected to experiment some of these insects, 

 collected without the aid of vinegar, he :>aw that they ex- 

 hibited the same phaenonicna as those of the shops. He 

 was therefore obliged to renounce his first idea, and to at- 

 tempt to ascertain by experiments the nature of the acid 

 presented to him. It, however, appears that all his efforts 

 in this respect were entirely fruitless; for he at length con- 

 cludes that he is not yet enabled to give a decisive opinion ; 

 and that, though the acid in question has some analogy 

 with the phosphoric, he 'hinks that it does not possess all 

 its properties, and therefore that it ought to be placed in a 

 particular class, until that which it ought to occupy shall be 

 fixed by new experiments. 



The third product of cantharidcs, called by Thouvenel and 

 Beanpoil the green matter, does not seem to experience any 

 alteration in the air, at least in its physical properties. It 

 is insoluble in cold water; it liquefies in hot water, on which 

 it floats in the manner of oil : alcohol and ether both dis- 

 solve it, and in these two menstrua it is decomposed by 

 water. Oxvgenated muriatic acid brought into contact 

 with this matter, and renewed from time to time, does not 

 at first appear to have any action on it; but small whitish 

 and shining scales, which fall to the bottom of the vessel, 

 are o-raduallv seen to detach themselves from it : in less than 

 eight days it loses its odour and colour, becomes thick and 

 glutinous, and, notwithstanding several lotions, it alwavs 

 retains the odour of tlic oxygenated muriatic acid. 



Diluted nitric acid assisted by heat gives it a russet colour, 

 a rancid and puiijrent odour, and even a pretty strong con- 

 sistence. 



Caustic soda unites with it without the aid of heat, and 

 without the disengagement of ammonia. The product of 

 this union is decomposed by acids. 



When exposed to the highest degree of heat it fuses and 

 forms a liquid, as it were, oily and slightly transparent, which 

 bv cooling soon resumes the solid state. In a stronger heat 

 it is df'composed, its colour changes, and there passes over 

 into the recipients a yellowish oil, verv analogous to that 

 furnished by yellow wax when distilled, an acid phlegm, 

 but not an atom of carbonate of ammonia. 

 . In regard to the parenchyme, which forms the residuum 

 of the difierent macerations, infusions, and decoctions, in 

 •woter^ alcohol, and in ether, the author, after ascertaining 



tliat 



