« 2% «

In more severe cases there may be vomiting, fever, fainting, and per-

sistence of the other symptoms.

The physiological effects of low pressure are due to the low partial

tension of oxygen. This causes a deficiency of oxygen in the blood (anox-
emia). The body tries to compensate for this cmdition by:

ass

(a) Increases respiration
(b) Chemical alterations in blood (lowering alkaline reserve)
(c) Increased hemoglobin (increase in red blood cells)

Increased Pressure
Increased pressure is of importance chiefly in the industrial field
(a) Tunnel workers
(b) Deep sea divers

The subjecting of the individual to high pressures results in a con-

dition called Caisson disease or “bends,” the latter name given by workmen
from the excruciating pains causing the individual toe double up his body.

Symptom s

(a) Slow respiration

(b) Slow pulse

(c) Peins in ears

(d}) Headache ami dizziness
(e) Excruciating pains

(f) Vomiting

Death may occur from internal hemorrhage or there may be paralysis

(diverts palsy).

Physiological effects are most marked am dangerous after decom-

pression. Effects are due to:

{a) Increase in amount of gases in blood (nitrogen)
(ob) Increase in chemical absorption of oxygen
{c) Air emboli

Prevention

(a) Gradually increasing pressure
{b) Gradual decompression

{(c) Caref’ 3: medical supervision

Temperature

The relation of temperature and light to health as two of the impor-

tant elements in climate can only be mentioned. The influence of climte on
the vigor and vitality of races is an interesting field of study. At this
time, we will only comsider the acute, extreme variations in temperature.

Low temperatures

(a) Chilblains

.