144 Analysis of the Atropa belladonna. 



These spicuhe progressively increase in size., and in s 

 short time exceed an inch in length. 



When we perceive that the metallic vegetation makes 

 no more progress, the piece of rag vvrth the spiculse may 

 be withdrawn from the liquor, and by means of a silk 

 thread fastened to the cork of the bottle, the whole may 

 be suspended under a bell glass. The crystals, which are 

 tetrahedrons, may thus be kept as long as wanted. 



I have in my own laboratory a crystallization of this 

 description, which has preserved all its original beauty for 

 these two years past. 



It may be easily seen that, in the above process, the play 

 of attractions is a little different from the common method 

 as developed by M. Fourcroy in Systime des Connois sauces 

 chhniqnes. 



The solidity of the metallic crystals obtained by my me- 

 thod, compared with the softness of the threads, the assem- 

 blage of which forms the common arbor Diana?, led me to 

 think that the proportions of mercury and silver are not 

 the same in both cases ; and I would have endeavoured to 

 have ascertained the difference, if M. Vauquelin, to whom I 

 communicated the circumstance, had not intimated his in- 

 tention of taking up the subject at full length, and publish- 

 ing his experiments in some future number of the Annahs 

 de Cfiimie. 



The configuration of the above crystals also suggests 

 some interesting inquiries, which I may probably be able 

 to accomplish at a future time. 



XXV. Analysis of the Atropa Belladonna. By M. Vau- 

 quelin *. 



J. he experiments which I am about to detail were made 

 with a view to ascertain whether this plant, which is of 

 the same family with the tobacco plants, contained the 

 acrid principle which has been found in the latter, but 

 which, as will be shown in the sequel, it does not. 



1. The expressed and filtered juice of the belladonna has 

 a dark brown colour, with a bitter and nauseous taste. It 

 is freely coagulableby heat, and by the aqueous infusion of 

 gall nuts. 



2. The substance coagulated by fire in the juice of bella- 

 donna is of a yellowish gray, becomes black on desiccation, 



* Annates de Chivrie, tome lxxii. p. 96. 



and 



