extract by Murray and Howitz in 1893. In 1884, Sir Victor Horsley produced an experimental myxœdema by removal of the thyroid in monkeys, which were found to survive much longer than dogs. It was also found by Allara (1885), Ewald (1890) and others, that experimental thyroidectomy is negative in birds, rodents and herbivorous animals, and that, both in animals and man, operative myxœdema is produced less frequently as age advances. In 1888,[1] Sir Felix Semon, in an important collective investigation, showed that cretinism, myxœdema and operative myxœdema (eachexia thyreopriva) are one and the same. In 1889, Brown-Séquard, then aged seventy-two, found himself vastly rejuvenated as to general health, muscular power and mental activity, by the subcutaneous injection of testicular extracts, the active principle of which Poehl, the Russian physiologist, holds to be the substance spermin (C5H14N2). These experiments of Brown-Séquard easily lent themselves to ridicule, but he followed them up, even to the extent of giving pituitary extract for disease of that organ (1893), and it was his work upon these extracts which led him to formulate the following statement of the old Bordeu theory of internal secretions:
As theory goes, nothing new has been added to the doctrine of internal secretions since Brown-Séquard stated it in this form in 1891. In his essay on "Variation" (1868) Darwin seems to have had a glimmering of the idea when he stated that gemmules are transported from all parts of the body to the ovum to insure their reproduction (pangenesis), and the Bayliss-Starling doctrine of the "hormones" or chemical messengers, as we shall see, is not essentially different from that of Bordeu and Brown-Séquard.
From the time of Brown-Séquard on, experimental investigation of the subject moved so rapidly and in so many different directions that the general trend of the theory became obscured or lost in the details of controversy. And further obfuscation was brought about by the constant succession of dissolving views of the subject of carbohydrate