538 DR THOMAS R. FRASER ON THE ANTAGONISM BETWEEN 



obtained. This preparation contains a considerable quantity of fatty matter, 

 which prevents its complete solution in water ; and as the division into separate 

 doses of a mere watery suspension would lead to many inaccuracies, it was 

 found necessary to weigh the requisite quantity separately for each experiment. 

 It is also hygroscopic, which further required that it should be dried and kept 

 in an exsiccator, in order to ensure an unvarying preparation. Nearly all the 

 experiments in which an extract was used were made with one prepared in this 

 manner, and a sufficient quantity was obtained by one process to serve for the 

 entire research. A few experiments, however, were made with an extract for 

 which I am indebted to Dr Cook, of the firm of Messrs T. and H. Smith, of Edin- 

 burgh. It will be seen, from the description of these experiments, that Dr 

 Cook's extract is more powerful than that prepared by myself, and this may be 

 accounted for by the fact that absolute alcohol was employed in its preparation. 



The active principle, physostigmia,* whose sulphate was also used in this re- 

 search, was obtained by the following process. Alcoholic extract of physostigma 

 was mixed with distilled water, and the fatty matters were completely removed 

 by agitation with successive portions of sulphuric ether. An excess of bicar- 

 bonate of sodium was then added to the watery solution, and the resulting alka- 

 line liquor was shaken with successive portions of ether. The decanted etherial 

 solutions were washed with water, concentrated by distillation, and then evapo- 

 rated spontaneously, by which means a residue consisting of an impure physo- 

 stigmia was obtained. This was dried over sulphuric acid, and treated with 

 anhydrous ether, and on evaporating the etherial solution, a less impure physos- 

 tigmia was obtained in the form of a pale brown extract-like substance. From it 

 the sulphate was prepared by neutralising a solution in rectified spirit with very 

 dilute sulphuric acid, and evaporating at a low temperature. This sulphate is a 

 pale brown amorphous substance, readily soluble in distilled water. As watery 

 solutions of the vegetable alkaloids gradually undergo decomposition, it was 

 considered advisable to weigh separately the dose required for each experiment. 

 Physostigmia, in common with the extract, possesses the inconvenient property 

 of absorbing moisture from the atmosphere, and for this reason, the obviously 

 necessary precaution was adopted of keeping the sulphate in an exsiccator. 



The atropia was administered in the form of sulphate, which salt was pur- 

 chased from Messrs T. and H. Smith of this city. The doses were generally 



* This alkaloid was first separated by me in 1863 ; and in a paper published in 1864 (" On the 

 Moth of the Esere, or Ordeal Bean of Old Calabar," Annals and Magazine of Natural History, May, 

 1864), I named it Eserinia, from Esere, the usual name of the ordeal poison at Calabar. Since then 

 I have, in various publications, adhered to this name, and it has been almost invariably adopted by 

 French physiologists and chemists. The reasons in favour of designating an active principle, derived 

 from the vegetable kingdom, by a modification of the generic name of its botanical source are, however, 

 so numerous and weighty, that I have thought it right in the present communication to follow the 

 usual practice. This I have the more readily done, as the name physostigmia (or physostigmin) is now 

 commonly to be met with in the writings of German physiologists. 



