1813.] 



M, de Fourcroy. 



329 



tions are of considerable importance, and relate chiefly to animal 

 and vegetable cbenoistry. At the same time, it must be allowed 

 that Fourcroy and Vauquelin often fall into mistakes difficult to 

 be accounted for ; and that they do not in every case do justice to 

 their predecessors or contemporaries who had been occupied with 

 the same investigations. A complete enumeration of these dis- 

 sertations would probably be considered as too tedious. I shall 

 therefore satisfy myself with pointing out some of his most 

 important chemical discoveries and observations. 



1. He repeated the curious experiments of Berthollet upon 

 the evolution of azotic gas from animal substances. This disser- 

 tation contains very little new, and is remarkable for some 

 striking mistakes ; as for example, that azotic gas has the 

 property of giving a green colour to vegetable blues. If such an 

 observation was ever actually made, he must have been deceived 

 by a portion of ammonia mixed with the azotic gas. He 

 announced, soon after, that the air contained in the swimming 

 bladder of the carp is azotic gas. This paper contains several 

 absurd observations on the method of procuring azotic gas : as 

 for example, that the black oxide of manganese gives out pure 

 azote, if exposed to a heat below redness. 



d. He analysed a green coloured mineral from Auvergne, 

 which he found a mixture of arseniate of lead and phosphate of 

 lead, 



3. He affirmed that ammonia is decomposed by the oxides of 

 manganese, mercury, and iron ; and that these oxides, at the 

 5ame time, lose either the whole or a portion of their oxygen. 



4. He ascertained that the most common constituent of biliary 

 calculi is a substance very similar in its properties to spermaceti. 

 This substance, in consequence of a subsequent discovery which 

 he made, during the removal of dead bodies from the burial- 

 ground of the Innocents at Paris, namely, that these bodies 

 were converted into a fatty matter, got the name of adipocire. 



5. He found that vegetable juices frequently contain a sub- 

 stance which coagulates when the juice is exposed to a gentle 

 heat. This substance he considered as albumen ; but Proust 

 afterwards showed that it was, in reality, a species of gluten, and 

 quite different in its properties from albumen. 



6*. He ascertained the properties of several triple salts, which 

 magnesia, and ammonia, and an acid, are capable of forming ; 

 and explained, by this discovery, the reason why mfignesia is not 

 precipitated completely from its solutions by ammonia. This 

 paper, which appeared in the fourth volume of the Annales de 

 Chimie, I consider as one of the best ever published by 

 Fourcroy. 



7.» He published a very elaborate analysis of the quinquina^ a 



