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Scientific Memoirs by

this time varies with the temperature, as uniform a temperature as possible is
advisable. " Half blood temperature," 18.5°C (65.°F) is recommended by Dr.
Wright, is obtained by placing the tubes in small pockets of a bandage fitted
around a metal vessel which can be filled with water of the desired temperature.

       One other fallacy has to be eliminated, namely, the effect of a full meal in
slightly accelerating, and of a prolonged fast in retarding the coagulability of the
blood. I made some preliminary observations to determine the extent of this
influence. Thus one day I had tea and toast at 7 A.M., breakfast at 9-30,
and then fasted until 8 P. M., taking two-hourly observations which resulted
as follows: At 9 A.M. my coagulation time was 4 min. 15 sec., at 11-30 A.M.
=4 min., at 1-30 P.M.=4 min., at 3-30 P.m.=4 min., at 5-30 P.M.=from 4
min. 15 sec. to 4 min. 30 sec., at 7-30 P.M.=4 min. 15 sec., and at 10 P.M.
=4 min. Thus the greatest variation was less than half a minute, and by taking
a light lunch at 2 P.M. even this difference may be lessened.

       Again, exercise might possibly influence the coagulation-time, but the
following observation seems to show that it exerts no material effect on it.
Thus a 14 mile march followed by being out shooting from 11-30 A.M. to 5-30
P.M. one day, and a 13½ mile march the next morning produced no alteration
of my coagulation-time. Alcohol has been shown by Dr. Wright to retard
coagulation, so throughout the 7 months over which my experiments have
extended I have taken no alcoholic drinks. In fact from nearly 150 observations
I have come to the conclusion that at a given temperature my coagulation-time
is remarkably constant, and as no conclusions have been drawn from less than
three experiments with the same drug, and from an acceleration of less than
from a half to one minute, all known sources of fallacy may be fairly claimed
to have been excluded.

       I now pass on to the consideration in detail of the results obtained, begin-
ning with the class of so-called hæmostatics, as the main object of this investi-
gation was to determine in what degree, if any, the power of these drugs in
checking internal hæmorrhage depends on their effect in accelerating the clotting
power of the blood, the rapidity of this action, and how long it continues. As
yet I have only determined this for single doses.

Calcium Chloride.

       This salt is the most powerful coagulation accelerator known, as has been
fully shown by Dr. Wright,*with the exception perhaps of the inhalation of
carbonic acid gas.†I will give one typical experiment here which I did at
Netley in 1893 to illustrate its range of action.

       Experiment. —My coagulation-time having been found to be 5¼ minutes both
in the morning and afternoon, I took 1 gramme (15 grains) of calcium chloride
at 7 P.M. and the same dose again at 7 A.M. the next day. At 3 P.M. my

*British Medical Journal, 1893, Vol. II, page 223.

†British Medical Journal, 1894, Vol. II, page 57.