ASPARAGUS. 243 



secretion of the saliva ; it is hard, brittle, and of a regular 

 form. 



The other kind which is also white, is not so transpa- and of the 

 rent nor hard, neither has it the same form ; on the con- ^^^^^' 

 trary, it has little consistence, is crystallized in the shape 

 of fine needles, and its taste is perceptibly saccharine, 

 resembling that of manna. 



Mr. Robiquet in making the analysis we have alluded 

 to, had noticed the first of these substances, but he took 

 it for an ammoniacal salt, because in the very small quan- 

 tity of imperfectly purified crystals he could then obtain, 

 it retained between its plates. According to all appear- 

 ance, some traces of salt with base of ammonia, with 

 which the juice of asparagus abounds, and which misled Figure of the 

 him. Since that time we have in conjunction submitted ^"{^13!" 

 this substance to new experiments, the principal of which 

 follow. The form which it effects in its crystallization, 

 according to M. Hauy, to whom we sent a certain quan- 

 tity, is derived from a right rhomboidal prism, of which 

 the great angle of the base is about 130 degrees. The 

 borders of this base, and the two angles, situated at the 

 extremity of its greater diagonal, are replaced by facets. 



This substance is moderately soluble in water, and its They are sola- 

 solution gives no signs of acid or alcali. The infusion of ^^^^" water, 

 nut galls, the acetate of lead, the oxalate of ammonia, the add nor alka- 

 muriate of barytes, and the hydro-sulphuret of potash, line, 

 produced no change in its solution. Alcohol does not 

 dissolve it. 



As these experiments indicate that the substance in They are not 

 question is not a salt with an earthy base, we triturated earthy iior anv. 



. , -ill,-, moniacal. 



a certain quantity with caustic potash and a little water, 



in order to see whether ammonia would be disengaged; 

 but no traces were exhibited. The potash appeared to 

 ns to render it more soluble in water. 



As we saw that it contained neither earth nor ammonia, »-nor neutral, 

 we directed our enquiries to ascertain the existence of the 

 alcalis, and for that purpose w^ burned a somewhat con- 

 siderable quantity in a crucible of platina. At first it 

 swelled up and emitted penetrating vapours which affected 

 the eyes and the nose like the smoke of wood. It af- 

 .forded a large portion of charcoal, which had no taste and 



left 



