while life continues, it is the physician's part to rule or regulate the reciprocal actions between external agents-climate-food-air-and blood; and between the elements of blood and the pre-formed textures.

CHAPTER III.

PRACTICAL PSYCHOLOGY.

"The testimony of natural reason must of necessity stop short of those truths which it is the object of revelation to make known; but, while it places the existence and principal attributes of a Deity on such grounds as to render doubt absurd and atheism ridiculous, it unquestionably opposes no natural or necessary obstacle to further progress. The character of the true philosopher is to hope all things not impossible, and to believe all things not unreasonable."-HERSCHEL.

SECTION I.

CAUSES INORGANIC, MORPHOLOGICAL, EMOTIONAL, AND

MENTAL.

MAN is a subject for study and contemplation in two distinct points of view. First, as an individual possessing a conscious unity-a personality insusceptible of division or analysis. Secondly, as a living being composed of parts, and subject to the laws of

matter.

The unity of consciousness, and the high truths of faith and revelation, are far beyond the sphere of reason or scientific inquiry, and in no way interfere

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with the expedients of a philosophical classification. But to a bodily structure, composed of various parts, and having different kinds of perceptions and sensations, scientific rules are applicable; and if, as in the practice of medicine, we be required to assuage a pain, alter a sensation, and stop the progress of disease-we must, to the utmost extent, analyse the phenomena of life in a twofold-a somatic and psychological point of view-classify the facts and form a theory of causes.

In studying the phenomena of external nature, every thing exhibits a multiplicity of operations and changes, an endless divisibility of parts, and the influence of motion, numbers, and arrangement, in the production of sensible effects. But when we turn inward upon ourselves, and contemplate the feelings and consciousness of self, although we meet with great complexity and variety, yet here there is a principle of unity, an individuality in which all feeling centres. This perfect conviction of unity and identity, springing up, as it were, or maintained and supported by such a multiplicity of parts and operations, is incomprehensible to our reason, the great mystery of man's nature, and beyond the range of his inductive inquiries. After many reiterated but fruitless attempts, from Aristotle down to the present time, to reconcile the qualities and appearances of things without, with the oneness of consciousness and thought within, and to remove the veil thrown over the inscrutable union of the living body, with the intellectual

power which governs and controls its movements, the effort has been found hopeless, and has been abandoned.

It is not my intention to enter into any metaphysical disquisition, yet I cannot omit here observing, that volition may properly be considered under two distinct points of view; thus a man may will to speak, or be silent, to take off, or put on his hat; and he has at his command the structural power and bodily configuration to realize his wish; if he has not, he is paralytic, or his body is diseased. But if he wills to visit the moon, to fly through the air, or stay his descent when falling from a height, his will must remain a wish or a desire, for he has neither structural power nor bodily conformation to accomplish such a wish. In the former case, his inability is a deprivation and a loss, which may possibly be remedied; in the latter, it can hardly be viewed in the same light; at all events it is irremediable. Corporeal or structural power, therefore, limits the operations of volition; but the boundary of knowledge is the only confine to our desires.

The Christian philosopher pursues his investigations with a settled belief that an ALMIGHTY CREATOR exists; and having in view only the discovery of those general laws, which may be deduced by the contemplation of a particular class of facts, or series of phenomena or appearances, he does not speculate on the abstract nature of matter or force; neither does he

try to know what becomes of this or that invisible power, when, as in the example of the voltaic pile, he is able at his will to concentrate and direct, or to dissipate and annul it; nor, when he heats and cools a bar of iron is he disappointed because he is ignorant of the nature of heat, and cannot tell whence it comes or whither it goes. On the contrary, he knows that in all, even in the simplest or most common cases, there must be residual phenomena or ultimate facts, quite beyond his comprehension; he, therefore, does not doubt the possibility of forms of power existing in a very different state, and under very different arrangements to any he witnesses here. "The possibility," to use the words of a distinguished writer," of the occasional direct operation of the Power which formed the world, in varying the usual course of events, it would be in the highest degree unphilosophical to deny." * But belief beyond reason is based upon grounds entirely distinct from those arising within the scope of any experimental research; the object of which is, in all cases, to remove the antecedent or the primary phenomenon as far back as possible, and to discover combinations, appearances, and results, as they are, without questioning those which a Supreme Intelligence has willed they shall be.

Bearing in mind, then, the true aim and scope of all inductive researches, it is evident, to whatever ex*Inquiry into the Relation of Cause and Effect, by R. Brown, M.D., F.R.S.