23

followed in every case. The time required for coagulation in Europeans is
usually stated to be from 4 to 6 minutes.

       In the Bengali the clotting of the blood is very much quicker than in the
European. The average time of coagulation obtained in our series is from
1¾—2¼ minutes. These observations were all carried out at blood heat.

       The short time required for clotting in the Bengali is well-known to all
workers on blood; the ordinary finger-prick, from which in the European a com-
paratively large quantity of blood can be obtained, in the Bengali rapidly closes
and becomes sealed by a clot.

       The cause of this rapidity of coagulation is difficult to explain. One factor
probably is the numerically high limits of the corpuscular elements and more
particularly the numerically high average of the white corpuscles in the blood
of the Bengali. Another factor which we consider of great importance is the
greater salinity of the blood found in the people of this province. The effect
of this increased salinity is in all probability to increase the degree of alkalinity
of the blood and also to increase the facility with which the blood clots. It may
be that with this increased salinity we have at the same time a higher concentra-
tion of calcium salts in the blood of the Bengali than in the European; any
increase in the number of calcium ions present, within certain limits, will favour
coagulation just as a deficiency seems occasionally, as in hæmophilia, to be
responsible for a diminished coagulability of the blood.

       5. The blood pressure in the Bengali.—In healthy adult male Europeans
the normal average pressure of the blood in the brachial artery varies from 110
to 130 mm. Hg., in the sitting posture. This pressure varies comparatively little
in health for the same individual when measured under similar circumstances and
on the same artery.

       We have taken readings of the blood-pressure in the brachial artery in over
500 adult male Bengalis. The instrument used was Riva Rocci's sphygmoma-
nometer with Recklinghausen's broad armlet. The pressure was noted at the
disappearance of the pulse in the radial artery—the arm being placed on a level
with the heart. All readings were taken with the person examined in a sitting
position.

       On the whole series the average blood pressure (systolic) of the Bengali
works out to be just under 100 mm. Hg., a good average systolic pressure in the
brachial artery lying between 95 and 105 mm. Hg.

       The blood-pressure of Bengalis is therefore on a much lower scale than is
the case in the European — a condition that must affect their vigour and
energy. The factors in the causation of the lower type of pressure of the
Bengali are, probably, manifold. That difference in climatic conditions is not
the chief cause is shown by the fact that Europeans living in the same