New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1906-10-21
CATSSON DISEASE.

Inc WOrk OF seNeIdl uiA
der rivers, requiring the use of caissons. or "a1r
locks" has caused a relatively rare disease to
become common in New York and the subject
of some general interest The bends" as this
malady is called by workmen, was first OBJ
served among pearl divers, but it was a con-
siderable time before medical men understood
the cause of the peculiar condition., and then
it was by accident that the discovery was
made. 4 French investigator in physiology. NJ.
Bert, while studying the effects of increases in
air pressure on animals, had the good fortune
to have his apparatus explode. The dog in the
glass bell Of the compression pump died imme-
diately. The idea occurred to Bert that perhaps
he had simulated in this accident the conditions
which cause caisson disease, and he set to work
to find out of what his dog had so suddenly
died The only abnormal condition Bert could
find was the presence OF bubbles of air in the
heart and that this was an adequate cause for
death had been known since the time of Galen
careful repetition Of Berts experiment has
shown that the conditions he found are almost
always present when death results from sudden
decomposition
Studies made by medical men have confirmed
Bert's theory In its application to man. Under
ordinary conditions a certain amount Of air is
dissolved In the blood. II the external air press
ure be increased, as 1t is In a compression lock
to two or three times atmospheric pressure, the
result is that much larger quantity of air goes
into solution with the blood Then If decom-
preston (the return to normal atmospheric
pressure) is quick, the dissolved air escapes as
bubbles into the circulation and much harm
results to the individual In that these air bub-
bles act as foreign bodies IN the blood vessels
and obstruct the flow of the blood. At times
the escape Of the dissolved air from it's state of
solution in the blood is so violent that it rupt
ures blood vessel.
Since Bert's notable experiments many other
studies have been made with view of finding
means to prevent this malady. Until recently
the most notable data were those collected by
French engineer NJ. HerSent, who conducted
his experiments In the presence Of members Of
the Bordeaux faculty of medicine. But more
important In practical value are the experiments
of two London psychologists, Hill and Macleod
who found that monkeys could endure with ease
a pressure Of eight atmOspheres and suffer no
apparent injury to their health, provided the
decomposition were made slowly. Hill then
had constructed steel cylinder Of Il cubic feet
capacity with motor driven pump for effect
Ing air compression. In this cylinder Hill and
his co-worker, Greenwood subjected themselves
to varying degrees Of pressure up to ninety
pounds. which is equivalent to water depth
Of more than 200 feet Both Of these inveSti-
gators recorded their sensations while under
pressure in the cylinder. One curious fact often
noted by those who work in caissons is ex-
planned. In q caisson where the pressure is
above three atmospheres it is quite impossible
to whistle Hill finds this is due to an inter-
ference with the vibration Of the lips; at higher
degrees Of pressure speech becomes difficult
also. After numerous experiments on them
selves these authors conclude that there is no
danger to healthy men IN barometric pressures
of at least seven atmOspheres, provided there
IS rigidly observed a gradual decomposition
period 1t is most emphatcally affirmed by
Hill that every death or case OF paralysis from
air embolism must be set down to negligence
of the contractor
1t has been repeatedly noted by Psychologists
in New York that persons dead of caisson dis
ease frequently show evidences of pulmonary
tuberculosis This is reason for most care
full physical examination of tunnel workers
in order that only sound, healthy men may be
employed The evidence all goes to prove that
if proper precautions were always exercised to
compel employees to undergo decomposition
slowly the bends would be an almost unheard
of disease.