288 Mr. W. E. Dixon. The Pharmacological _[Nov. 1, 
ceases and death occurs from asphyxia. Boxwood has no specific affinity for 
cardiac or other muscle. 
The two samples of alkaloid I used, Mr. Harrison informs me, were 
prepared as follows :— 
“A” was prepared by heating the sawdust with dilute hydrochloric acid, 
straining and pressing; the acid liquid was then concentrated, filtered from 
the resinous matter which separated, and precipitated by potassium bismuth 
iodide solution ; the precipitate was decomposed by sodium hydroxide and the 
alkaloid extracted by alcohol; the alcoholic solution was evaporated, the residue 
extracted with dilute hydrochloric acid, leaving resin undissolved, and the 
alkaloid liberated from the solution by ammonia and shaken out with 
chloroform; the alkaloid was further freed from resin by repeating the 
treatment with acid, ammonia, and chloroform. When finally converted into 
hydrochloride the solution deposited a little more resin on standing, which was 
filtered off. 
“B” was prepared by percolating the sawdust with alcohol, evaporating 
the alcoholic liquid, and taking up the residue with dilute hydrochloric acid, 
leaving resin; the acid solution was then precipitated with phospho-tungstic 
acid, the precipitate decomposed with sodium hydroxide and the alkaloid 
extracted by alcohol; the subsequent treatment was the same as for “A.” 
The experiments were performed on cats, dogs, frogs, and rabbits, which, 
unless otherwise stated, were anesthetised with A.C.E. mixture and later with 
urethane. 
Effect on the Circulation.—The injection of small doses of the alkaloid, 
from 10 to 20 milligrammes, into the circulation of the dog or cat causes a 
rapid and considerable fall of blood-pressure ; the pressure rises again slowly, 
but never to its former height. Further injections produce less and less 
effect on blood-pressure until, after 40 or 50 milligrammes in the case of the 
cat, a point is reached when further injections are without decided influence 
(fig. 1). 
A fall of blood-pressure of this nature is characteristic of the group of drugs 
which paralyse autonomic nerve cells, such as curare, apocodeine, coniine and 
the like, and should be entirely vaso-motor in origin. That there is consider- 
able vaso-dilatation of the splanchnic area can be readily shown either by the 
oncometer or the method of perfusion. This may be inferred from the 
increased volume pulse of the intestinal vessels shown in fig. 4B. In 
plethysmographic tracings it is clear that the fall of blood-pressure 
corresponds fairly accurately with the degree of dilatation. 
Perfusion experiments in which oxygenated Ringer’s solution is forced at 
constant pressure through the intestinal or limb vessels of a rabbit also show 
