PHYSOSTIGMA 411 



broad, and 10 to 15 mm. thick; oblong and somewhat reni- 

 form; testa granular, chocolate-brown, with a broad, black 

 groove extending over the entire length of the convex edge. 

 Embryo with a short, curved radicle and two large, white, 

 concavo-convex cotyledons ; inodorous ; taste bean-like. 



Constituents.— The principal constituent is the alkaloid 

 physostigmine, or eserine. There are also the alkaloids 

 calabarine, a product resulting from the decomposition of 

 eserine, and eseridine, similar in action to eserine, but 

 weaker; and a neutral principle, physoterin, resembling 

 cholesterine. 



Calabar Bean Dose. — H., gr.xv.-xxx. (1.-2.)- D gri-i 

 (.015-.06). ' ft -5 • 



The official preparations are the extract and tinc- 

 ture of physostigma, but physostigmine is solely used in 

 veterinary medicine, since it is more certain and generally 

 free from calabarine, which produces, in toxic doses, a 

 tetanic condition followed by paralysis. 



Physostigmine Salicylas. Physostigmine Salicylate 

 C,,H,NAC,HA- (U.S. P.) 



Synonym. — Eserine salicylate. The salicylate of an 

 alkaloid obtained from physostigma. 



Derivation. — Physostigmine is obtained from the alco- 

 holic extract of Calabar bean by dissolving the extract in 

 water, adding sodium bicarbonate, shaking the mixture with 

 ether, and evaporating the ethereal liquid. The salicylate 

 of the alkaloid — the most stable salt — is made by adding 

 physostigmine to a solution of salicylic acid in boiling 

 distilled water, when the salt crystallizes on cooling. 



Properties. — Colorless, or faintly-yellowish, shining, aci- 

 cular, or short, columnar crystals; odorless, and having a 

 bitter taste. Soluble in 150 parts of water, and in 12 parts 

 of alcohol ; in 30 parts of boiling water, and very soluble in 

 boiling alcohol. (U. S. P.) . 



Z»osp. — H. & C, gr.i.ss.-iii. (.09-. 18); D., gr.T^-o--^ 

 <.0006-.002). 



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