Page:Dictionary of National Biography, Third Supplement.djvu/234

 October 1874 went to work with Karl F. W. Ludwig, professor of physiology at Leipzig, returning to Cambridge the following summer. In 1875 he married Catherine Sharpe, daughter of Reginald Amphlett Parker, solicitor, and settled in Grantchester in order to work in the Cambridge physiological laboratory. He proceeded to the degree of M.D. in 1878, and five years later (1883) was appointed university lecturer in physiology, the only teaching post he ever held. In 1889 Trinity Hall elected him to a fellowship. After living for a few years in Cambridge, he built ‘The Uplands’, Great Shelford, where he remained until his death (from cerebral haemorrhage) on 7 September 1914. He was survived by one son and two daughters.

It was Ludwig’s custom not only to suggest to his pupils the subject of research, but to carry out most of the experiments and to write the papers which appeared under their names. Gaskell, who was set a problem in vascular innervation, pondered deeply over the subject and, on his return to Cambridge, devised an ingenious method of watching the blood-flow in the mylohyoid muscle of the frog during stimulation of its nerve. He then turned his attention to the heart, and demonstrated by many beautiful experiments the inherent rhythm of cardiac muscle and the influence on it of nervous impulses and drugs. He proved that the normal beat started in the sinus and was propagated by way of the muscular tissue of the auricle to the ventricle. This work led to his being elected a fellow of the Royal Society in 1882.

In the course of these researches Gaskell discovered that the vagus nerve of the frog contained two sets of fibres, which not only produced an opposite effect on the action of the heart, but differed in structure and in their origin from the central nervous system. He therefore extended his inquiry to viscera other than the heart. The movements of these organs were generally thought to be governed by a ‘vegetative nervous system’, which lay outside and was largely independent of the brain and spinal cord. Gaskell revealed on broad lines the true plan of their relationship to the central nervous system, and showed that, like the heart, they were all supplied by peculiar motor and inhibitory nerves arising from specially restricted areas of the same nerve-axis as that which governed the ordinary muscles of the body.

Gaskell did not pursue the details of this visceral innervation with the same minute experimental attention which he had given to the heart, but passed on to inquiries of a still wider scope, the consideration of function from its developmental aspect. It had been taught that one set of nerves quickened and another stopped the heart; Gaskell’s aim was to discover not only the mechanical means by which this was brought about, but how these functions arose. This method of considering physiological problems had a profound effect on scientific medicine. Gaskell revolutionized current ideas of the action of the heart, and, consequently, of cardiac disease. He laid bare both the structure and functions of the involuntary nervous system. Never content simply to record a new fact, he always asked the meaning of the phenomena which he described.

From these studies Gaskell was led to consider the mode by which vertebrate animals derived from an invertebrate ancestry; for he argued that many apparently anomalous structures in the nervous system must be relics of some more primitive state. In 1889 he put forward the first indications of his theory that the vertebrates are descended from an arthropod stock, of which the king crab is the nearest living example. He accounted for the obvious differences in the relation of the principal organs by supposing that the gut of the arthropod, surrounded by its chain of ganglia, had been transformed into the central canal of the spinal cord. This theory raised a vehement storm of protest from certain zoologists, which grew in volume as new points were brought forward by Gaskell in paper after paper. Finally, when he published The Origin of the Vertebrates in 1908, the work passed almost unnoticed. This book is written in a fascinating manner, clear, simple, and concise. Whatever may be the ultimate fate of Gaskell’s hypothesis it contains innumerable original observations marshalled with unusual skill. Shortly before his death he completed the manuscript of a small book, embodying the results of all his researches, which was published in 1916 under the title of The Involuntary Nervous System.

Gaskell’s robust frame, sanguine complexion, and abundant dark hair and beard, which never went entirely white, gave him the appearance of a man whose occupation was in the open air; and indeed digging and the care of his garden formed his principal recreation. The clarity and half-veiled enthusiasm of his exposition, together with his somewhat 208