DAVID CERNA-PHYSIOLOGICAL ACTIONS OF SPARTEINE. 
69 
The blood-pressure .—The arterial pressure is generally increased by 
small doses of sparteine, this phenomenon being more or less marked ac¬ 
cording to the quantity of the agent administered. The drug sometimes, 
however, instead of an increase, causes from the outset a decrease of the 
blood pressure. When an increase is produced, the normal standard is 
obtained after a certain length of time. Even large and poisonous 
amounts of sparteine produce often a brief rise in the column of mercury, 
which is soon followed by a decided fall, this continuing till the occur¬ 
rence of death. The fall, however, if the dose has not been fatal, is also 
recovered from in the course of time. The changes observed, as in the 
case of the pulse, are not constant, and, again, may be said to depend on 
which part of the mechanism influencing the arterial pressure is being 
acted upon at the time. 
Let me examine into the primary elevation of the pressure caused by 
sparteine. Various causative factors must be taken into consideration in 
explaining this rise. Physiologically, the phenomenon may occur: 
(a) from a direct action on the heart itself or its controlling nerve-mechan- 
sm; ( b) from a stimulating influence exercised on the vaso-motor system, 
Fig. O. 
Tracing III.—The same 8 minutes after the injection, showing the fall of the 
pressure, the diminution of the pulse-rate, and the large size of the individual 
waves, as in Tracing II, Figs. E, F, G, and II. (Normal experiment.) 
whether centrally or peripherally; (c) from a direct action on the mus¬ 
cular coats of the arterioles. The first action, by augmenting the vis a 
tergo force , will naturally increase the resistance in the capillary blood 
vessels; and as a result of the second and third actions there will be pro¬ 
duced a contraction of the arterioles, causing also an increase of resist¬ 
ance. In any one of the three instances the arterial pressure will rise, as 
shown in the distinct elevation of the column of mercury in the manom¬ 
eter. 
It is quite difficult to ascertain with accuracy whether the muscle-coats 
of the arterioles are ever influenced exclusively of other changes occur- 
