Rensselaer Semi-Weekly Republican, Volume 39, Number 61, Rensselaer, Jasper County, 5 April 1907 — WHAT CAUSES “THE BENDS.” [ARTICLE]

WHAT CAUSES “THE BENDS.”

Frenchman Discovers Him the Caisson Disease Orlfrlnntes. The work of constructing several tunnels under rivers, requiring the use of caissons or “air locks,” has caused a relatively rare disease to become common in Now York- and the subject of some general interest. The "bends,” as this malady is called by workmen, was first observed among pearl divers, but it was a considerable time before medical men .understood the cause of the peculiar condition, and then it was by an accident that the discovery was made. A French investigator in physiology, M. 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 immediately. 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 oi what his dog had so suddenly died. The only abnormal condition Bert CQttld 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. A careful repetition of Bert’s" experiment has shown that the conditions be found are almost always present when death results from sudden decompression. 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. If the external air pressure he increased, as it is Jn a compression lock, to two or three times atmospheric pressure the result is that a much larger quantity of air goes into solution with the blood. Then if decompression (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 bubbles act as foreign bodies in the blood vessels and , obstruct the flow of the blood. At times the escape of the dissolved air from its state of solution in the blood is so violent that It ruptures a blood vessel.— New York Tribune.