The investigations hereafter recorded were made
with the object of determining what effect, if any,
certain drugs, commonly supposed to act as blood
pressure elevators, have on the systolic and diastolic
pressure of healthy individuals.
lay observations have been limited to the immediate
effect of the drugs experimented with, as one of the
objects of the research was to endeavor to compare
their values as possible remedies for combating
dangerous hypotension.
Most of the statements made regarding the pressor
action of certain medicaments are based on the results
of laboratory experiments on animals, and the conclusions
so formed, as has been frequently demonstrated,
do not always hold when drugs are given to patients
in ordinary doses.
My observations have been made on persons with
normal arterial tension rather than on patients
suffering from marked hypotension; partly because of
the difficulty or impossibility in such cases of
insuring with reasonable certainty that the blood
pressure of the patient remains unaffected by anything
but the drug administered, but chiefly because the
condition of the vessels in cases of marked hypotension .
has not yet been definitely determined. Until recently
Crile's theory (Surgical Shock, 1899), that the
vessels are relaxed in those cases as a result of
exhaustion of the vaso-motor centre, has been generally
accepted; but the opposite view first put forward by
Malcolm (The Physiology of Death from Traumatic Fever,
1893), that there is a general contraction of the
vessels, has now many supporters.
Most of my observations were made on the effect
of drugs on my own blood pressure. I am 26 years of
age, in sound health, and have an average systolic and
diastolic pressure of about the generally accepted
normal. In a few instances the conclusions arrived
at were confirmed by observations made on other
healthy individuals. In order that the results
obtained might be comparable, every care was taken
during the investigations to maintain as nearly identical
conditions as practicable, and to exclude as well
as possible all transitory factors influencing the
normal arterial tension.
There is not, as far as I am aware, any published
record of a similar series of investigations, but
Edgecombe (Practitioner, April 1911, pp. 531 -536) has
recorded his observations on the sustained effect of
certain reputedly pressor drugs when administered for
several days to a subject with a persistently low
blood pressure
