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It was but a step, we can now realize, from the employment of isolated vegetable principles to that of preparations of certain glandular organs of the animal economy, but the doctrine of "internal secretions" had to intervene, and its evolution took time; not till toward the close of the century did the venerable Brown-Séquard lead up to it.
The idea of employing the chemical materials of the sex glands, the testes or the ovaries, to bring back youth, to restore juvenility, had not, as far as we know, occurred to anyone who at any rate put himself on record, by word or deed, until 1889. The hero of the new departure was the hero of so many daring adventures among speculative experiments, Brown-Séquard.
Such a result does not, however, explain why the offspring should suffer from the same disease as that which was artificially induced in the parents. But this does not appear to have been by any means invariably the case. Brown-Sequard himself says: 'The changes in the eye of the offspring were of a very variable nature, and were only occasionally exactly similar to those observed in the parents.
They also demonstrate that the internal secretion of the sex glands, well advertised as it has been as the Elixir of Youth that Ponce de Leon, and Brown-Séquard with so many others, pursued in vain, is not the whole story. For if it was, the duration of the new youth should be another span of life, whereas in actuality it is only a fraction of that time.
Some experiments of Voisin and Peron have shown that fits of epilepsy are followed by the elimination of a toxic body which, when injected into animals, is capable of producing convulsive symptoms. Perhaps the trophic disorders following the nerve lesions made by Brown-Séquard correspond to the formation of precisely this convulsion-causing poison.
But a clear light was not thrown on the subject until Bernard's experiments were made in 1851. The experiments were soon after confirmed and extended by Brown-Sequard, Waller, Budge, and numerous others, and henceforth physiologists felt that they understood how the blood-supply of any given part is regulated by the nervous system.
Among the many important properties of the nervous system which have either been first discovered or strikingly illustrated by Dr. Brown-Séquard, I select the reflex influence of the nervous system on nutrition and secretion.
Brown-Sequard observed on several occasions in his own dark beard hairs which had turned white in a night and which he epileptoid.
Brown-Sequard, who immediately came from New York, and Dr. Morrill Wyman; and the last few days of his life were passed, not in great suffering, with his loving family around him. Nothing, however, could arrest the progress of the malady.
It is not, therefore, simply the power of performing an action which is inherited, but the power of performing a whole series of actions, in a certain order. "In most of the cases of inheritance recorded by Brown-Sequard only one of the two parents had been operated upon and was affected.
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