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Show Keeping Up llnienJ:e Science Service. WNU service. Newly Found Nerves Act as "Spares" to Speed Heart Action Tests on Dogs Reveal Their Dual Function NEW YORK. Science's first step toward an understanding under-standing of recently discovered nerve fibers for speeding up heart action, a discovery which may lead to their identification as hitherto unknown sympathetic sympa-thetic nerves, was announced to the New York Academy of Sciences here by Dr. Lucien A. Brouha of the University of Liege, Belgium. Discovered at the University of Ghent In 1934 by Jourdan and Nowak, the tiny fibers have remained re-mained pretty much of a mystery to science, the only definite fact known about them being their position alongside the vagi nerves which run from the brain to the heart and which serve to retard the cardiac beat. Even now, Doctor Brouha explained, ex-plained, little Is known of their function In the normal body but In dogs whose sympathetic nervous system has been removed, these new nerve fibers take Its place. Indeed, In-deed, go successfully do they substitute sub-stitute for the missing nerves that Doctor Brouha finds It absolutely Impossible to distinguish a normal dog from one without Its sympa- tnetic system. How Dogs React. It was the ability of the new nerves to replace the sympathetic system In dogs that led Doctor Brouha to his conclusion concerning concern-ing the possible function of the nerves as a substitute for the removed re-moved system. In the normal body, he believes, the nerves may aid heart regulation to a very small extent, ex-tent, although he said that In all probability they have additional functions as yet undiscovered by 6clence. In research leading to these results, re-sults, Doctor Brouha conducted pioneer treadmill tests on dogs both before and after removal of the sympathetic system. The experiments experi-ments were performed In co-operation with Dr. David B. Dill of the Harvard University Fatigue laboratory labora-tory where Doctor Brouha Is carrying carry-ing on his investigations this year. Outstanding among his finds were that the general behavior of a dog whose sympathetic chains have been removed remains normal, although the heart beat of the animal at rest Is slightly less than normal, and that emotional excitement produces the usual cardiac acceleration. Substitute for Regular Nerves. Another Important find was that the capacity to stand very Intense exercise Is not at all diminished three months after the removal operation, op-eration, that time being necessary for the dog to recover from the operation. op-eration. Experimentally checking the possible pos-sible influence of a rise In body temperature tem-perature or muscular metabolism. Doctor Brouha found that they are definitely not responsible for the accelerated ac-celerated heart beat. Nor are adrenalin adre-nalin or sympathin, for with the removal re-moval of the sympathetic system, these hormones are not secreted Into the blood stream. |