256 THE JOURNAL OF PHARMACOLOGY. 



this the per cent, calculated, instead "of calculating from the volume of 

 volumetric acid required to neutralize the residue. 



Of the assays of belladonna leaves published elsewhere the following 

 are noted : 



Coblentz 8 reports the assay of four specimens, German, containing 0.212, 

 0.42, o. 18, 0.109 percent., and two English specimens with 0.422 and 0.41 1 

 percent, of "purified alkaloid" by weight, or an average of 0.292 per 

 cent. 



Lyons 9 reports 26 assays showing a variation of from 0.23 per cent, as 

 the lowest to 0.87, the highest, or an average of 0.44 per cent, of alkaloid 

 " by weight." 



Thompson 10 reports twelve assays with a maximum of 0.5, a minimum 

 of 0.27 and an average of 0.40 per cent, of total alkaloid by weight. He 

 also mentions fifteen assays made in 1890 giving an average of 0.33 per 

 cent. 



It is to be observed that the assays so far quoted all report the amount 

 of alkaloid by weight, i. e., the alkaloid extracted from the drug by im- 

 miscible solvents is weighed, and that the results, compared with the 

 present method of assay, are much too high. In order to compare these 

 assays with recent ones, based on acidimetric titration, a specimen of bel- 

 ladonna (No. 15), which, according to my assay, contained 0.34 per cent, 

 of alkaloid, was assayed after the method used by Thompson ; it assayed 

 0.46 per cent., and accordingly all assays quoted above should be reduced 

 something like 25 per cent. 



Schwickerath 11 reports two specimens containing 0.34 and 0.37 per 

 cent, by acid titration. 



Beckhurst 12 finds three samples, to yield by acid titration, 0.486, 0.428 

 and 0.509 per cent. 



Keller 13 finds 0.38 and 0.40 per cent, of alkaloids. 



Nagelvoort 14 reports upon 25 acidimetric determinations ranging from 

 0.2 per cent, to 0.58 per cent., and averaging 0.35 per cent. 



If, in view of the above, showing the extreme variation of belladonna 

 leaf as found on the market, it be acceded that the adoption of an alka- 

 loidal standard is desirable, then the question arises as to the value to be 

 adopted. The mean of all assays of leaf quoted, good, bad and indiffer- 

 ent, will be about 0.3 per cent, and a lower standard should certainly be 

 adopted, and a requirement of 0.35 to 0.4 per cent, could easily be com- 

 plied with. I would recommend that the leaves and tops, collected during 

 or after flowering, be made official, as in this way by the presence of 

 flowers or seed capsules, the fully matured leaf may be recognized and 

 distinguished from the young luxuriant leaves which have been found 

 worthless. 



Provisionally I also propose that belladonna leaves be required to con- 



