braced all the elements of the excito-secretory function, viz: first, a sensitive nerve as an excitor; secondly, a cerebro-spinal centre; thirdly, the secretory nerves and ganglia. M. Bernard's experimental results were deficient in the first of these elements, viz., the sensitive nerve as an excitor.1 To illustrate the connection of these various parts with the two divisions of the nervous system, we have introduced another figure from page 322 of M. Bernard's excellent work: In transferring to our pages the next figure, we have omitted the explanations, but would here remind the reader that analogous relations subsist between the secretory filaments of the alimentary canal, not represented here, and the cerebro spinal centres and cerebro-spinal sensitive branches. We will make special reference to only one more set of pathological phenomena, as peculiarly illustrative of the excito-secretory function of the nervous system; we refer to some of those very mysterious aberrations of secretion found so uniformly concomitant with attacks of hysteria. Almost universal opinion has referred the manifesations of this disease to irritation of one kind or another, in the generative organs of females, viz., the ovaria, neck of the womb, and the uterus itself. It is a significant fact, that females laboring under this disease should so frequently manifest modification in their urinary secretion. "It appears, indeed," says Laycock, "that some alteration in the quantity or composition of the urinary secretion is one of the most constant symptoms of hysteria, even in its mildest form, when the patient can only be said to have a hysterical constitution." "Limpid urine," in large quantities, is nearly always a concomitant, and Dr. Laycock also refers to "the profuse sweats and salivation of hysterical females.” We regard all these secretory phenomena as fully explicable, by referring them in many instances to the excito-secretory function. The records of both physiological and pathological medicine, would furnish a still more abundant treasure of facts, which could be made to corroborate our views in reference to this function of the nervous system, but such an extended discussion would not be consonant with the object of the present paper. Our earnest endea. We have not tested in any instance the chemical properties of the urine of teething children, but we would here respectfully suggest that it will be found to contain sugar in those cases in which the increased urinary secretion presents a prominent feature in the concomitants of dentition. Op. citat., p. 86. vor has been to bring together from all sources, however diverse and unpromising, a sufficient number of kindred facts to establish, Fig. 6 Cerebro-spinal and Splanchnic Nervous Systems of a Rabbit, showing the nervous connections existing between the liver, lung, and kidney, to explain the production of artificial diabetes. more fully, perhaps, than has heretofore been done, the physiological and pathological relations of the excito-secretory system of nerves. This dissociation of old facts from their accustomed and apparently established relations, and the transferring of them to new ones, may have given to our discussion an aggressive aspect, by no means intended or contemplated by us. We disclaim all intention to underrate the importance of other investigations, or to misinterpret their results. We have, in a few instances, it is true, endeavored to the best of our ability to correct the conclusions of some who have preceded us, but never, for a moment, prizing less the real significance of the data in discussion. "The ultimate attainment of truth," writes the great Sir William Hamilton,' "has ever been by gradual approach," and, as not unkindred to our theme, we quote his apt illustration: "The history, in regard to the discovery of the distinction between sensitive and motor filaments in the nerves, finally established by Sir Charles Bell, was only the last of a long series of previous observations tending to the same effect;" or, in the words of Professor Whewell, "the facts were known, but they were insulated and unconnected till the discoverer supplied, from his own stores, a principle of connection. The pearls are there, but they will not hang together till some one supplies the string." By diligent observation and careful induction, we have, for years past, been endeavoring to find this principle of connection, and to place these pearls upon their appropriate string; if, in the earnest and honest investigation of a somewhat new and obscure subject, we have failed to develop all that the advantages, previous suggestions, and the rapid progress of science must unfold in this extensive field of inquiry, we can only refer to the recent expression of Dr. Marshall Hall, that "this vast subject demands a most extensive and cautious series of experiments and observations. The efforts of many laborers, through many years, will be required fully to develop the two sub-systems of the Diastaltic Nervous Systein." We must cordially agree with him, but would here humbly, but most earnestly ask, that "observation" be allowed to occupy her true and equal place by the side of "experiment" in all these investigations. 'Philosophical Works, p. 400, note. 2 Philosophy of the Inductive Sciences, vol. ii. p. 48. PRIZE ESSAY. EXPERIMENTAL RESEARCHES RELATIVE TO THE NUTRITIVE VALUE AND PHYSIOLOGICAL EFFECTS OF ALBUMEN, STARCH, AND GUM, WHEN SINGLY AND EXCLUSIVELY USED AS FOOD. BY WILLIAM A. HAMMOND, M. D., SURGEON U. S. A. Quem sequimur? quove ire jubes? ubi ponere sedes? |