127,

184,

22, before "the angle of the jaw," insert "In opening the mouth.” 24, for palate bone, read hard palate.

OUTLINES

OF

HUMAN PHYSIOLOGY.

CHAPTER I.

INTRODUCTORY OBSERVATIONS.

To investigate the changes which Animals and Plants exhibit, to ascertain the means by which the phenomena of Life are produced and the laws which regulate their succession, is the province of Physiology. The study of this ample subject requires considerable anatomical proficiency, or a knowledge obtained by dissection of the structure of animals and plants, as well as an acquaintance with their external appearance and habits, or with their natural history, and elucidates the principles of the various arts by which man improves or modifies the nature and physical character of living beings of other species, or relieves the infirmities of his own.

The present work, which treats of a part only of physiology taken in an acceptation so general, contains a

B

2

Tendency of Physiological Studies.

brief account of the human œconomy during health, intended to serve as an introduction to the study of disease. Independently, however, of a practical object, a speculative interest attaches to all researches of this nature, upon which I may be allowed to offer a few preliminary remarks.

He who examines the office of a single organ in an animal body, who investigates the laws of vision, or the means by which articulate speech is produced, experiences the same kind of surprise and delight, as upon witnessing some refined application of machinery. But while in the latter case his mind is occupied upon human invention only, and his surprise gradually gives place to a conviction that the design before him is yet imperfect, and admits of being simplified and improved,—in the former case his thoughts are raised to that Supreme Intelligence, which has fashioned elements that human hands cannot combine, for objects that human sagacity but partially comprehends; yet which, where understood, display in their attainment contrivance so perfect and infinite, as to lead irresistibly to a belief that nothing results fortuitously from properties inherent in matter, that Nature is the work of God.

The subsequent progress of a physiological student continually serves to illustrate the attributes of that Supreme Mind, whose marvellous design he is busied in unravelling. He reads in the careful provision for the perfectness and preservation of every species, and for the happiness of those which enjoy consciousness, a demonstration of an allwise benevolence; and he deduces from that remarkable analogy which pervades the innumerable families of living beings, stamping all in their

Tendency of Physiological Studies.

3

various gradations and diversities with one common mark and impress, a confirmation,-if the expression be allowable,-of his belief in the unity of the Deity. From points yet more abstruse the veil seems partially withdrawn: the nature of life, the relation of the soul to the body, are more than indistinctly unfolded to his view. Principles even of moral conduct derive support in some instances from the inquiries of physiologists, which explain the physical connexion between the improvement or degeneracy of races or of individuals, and the observance or neglect of rules derived from higher sources. every step is established some point of coincidence between the religion and morality of Nature and of Revelation.

At

Nevertheless it has been occasionally asserted, that the practical tendency of medical studies is to encourage irreligion, and that the theory of materialism is borne out by physiology.

The refutation of the first charge is easy by an appeal to facts. Harvey and Hales, Boerhaave, Haller, Baillie, are among the first names of eminent physicians or physiologists which occur to my recollection, and serve sufficiently to illustrate the frame of mind, as to religion, which has always attended genuine excellence in medical science.

The second imputation deserves to be examined the more attentively, because many are of opinion that the theory of materialism is essentially opposed to the doctrines of Christianity.

All who have reflected upon this subject concede, that mind and matter, the soul and the body, the phenomena of thought and a nervous system, are in the present state