Yet its anterior lobes may be destroyed without the senses losing their power of receiving impressions, and without the still-living creature ceasing to be conscious of them.* "The anterior or frontal part of the brain is hence inferred to be the seat of several intellectual faculties." The functions of the eye depend greatly on the part called the tubercula quadrigemina.‡

The CEREBELLUM, at the back part of our brain, is most connected with our bodily movements. §

The MEDULLA OBLONGATA is essentially concerned in the functions of our breathing, which cannot be continued without it; and it co-operates in what is performed by the spinal marrow.||

It seems to be the most important part of the brainous system in all the functional operations of our frame.¶

"The vital offices of the SPINAL MEDULLA are now reduced to conveying to the muscles the motive impulse of volition, and to propagating to the sensorium commune, impressions made on the external senses." "It does not originate muscular motions. It is divided by a double furrow into two lateral halves; and each of these is again subdivided into two columns, one posterior and one anterior."+t The sensations

"Animals thus mutilated, feel, see, hear, and smell; are easily alarmed; and execute a number of voluntary acts; but cease to recog nise the persons or objects which surround them. They no longer seek food, or perform any action announcing a combination of ideas."-Dr. Henry, p. 66.

"Its removal occasions a state resembling idiotism, characterized by the loss of the power of discriminating external objects; which, however, co-exists with the faculties of sensation."-lb. p. 66.

"The tub. quad. preside over the motions of the iris; and their integrity seems essential even to the functions of the retina."-Ib. p. 90.

It may be regarded as nearly established by modern researches, that the cerebellum is more or less directly connected with the function of locomotion. Rolando found that injuries of the cerebellum were always followed by diminished motive power."-Ib. p. 68.

"The medulla oblongata exercises the office of originating and reg ulating the motions essential to the act of respiration."-Ib. p. 91. "H is continuous in structure with the spinal marrow, and enjoys, by this relation, the same function of propagating motion and sensation."-Ib. p. 72.

"The cerebrum may act without the cerebellum; and this latter organ continues to regulate the motions of the body, after the removal of the cerebrum; but the functions of neither survive the destruction of the medulla oblongata, which seems to be the common bond and central knot, combining all the individual parts of the nervous system into one whole."-Ib. p. 72.

** Ib. p. 74.

tt Ib. p. 75.

from external things are conveyed to the soul by the posterior columns; and by the anterior ones, its will directs and produces the movements of its limbs and body.*

The nervous roots and their continued fibres or extensions spring separately from these distinct columns, and carry with them, as they spread and branch, their several properties and functions; the one sensorial, the other motive.t There is no necessary dependance of the motions of the heart, and the other involuntary muscles, on the spinal marrow."

Of the NERVES, some are nerves of motion only, and are confined to the performance of it; others, and a large number, are nerves both of motion and sensation, which proceed in their distinct columns from the spinal medulla; a few nerves minister to the senses of sight, smell, and hearing.¶ Here again is a remarkable instance of the designing and factitious structure, and specific composition and appropria tion of every part of our frame. "The olfactory, auditory, and optic nerves, are gifted with a special sensibility to the objects of the external senses to which they respectively minister. The one receives sensations from what is odour, and from that only; the second from sound, and from sound alone; the third solely from the impressions of sight; but

Henry, p. 76. "These two vital offices reside in distinct portions of the spina medulla-the propagation of motion in its anterior columns, the transmission of sensations in its posterior columns."--Ib. p. 91.

"Thus, each spinal nerve is furnished with a double series of roots; one set of which have their origin in the anterior medullary column, and one in the posterior. In consequence of this anatomical compo sition, the spinal nerves are nerves of twofold functions, containing, in the same sheath, distinct continuous filaments from both columns." Ib. p. 76.

1 lb. p. 91.

"The class of nerves exercising the single office of conveying motion, comprehends the third, fourth, sixth, portio dura of the seventh, the month, and perhaps two divisions of the eighth, viz. the glossopharyn geal and spinal accessores."--Ib. p. 80. "Three of these nerves, the third, sixth, and ninth, arise from a tract of medullary matter, continuous with the anterior column of the spinal marrow."--Ib. p. 83.

"There are thirty-two pairs of nerves, which possess the twofold office of communicating motion and sensation. All of these, excepting one, the fifth pair of the cerebral nerves, spring from the spinal marrow, These thirty-one pairs are all constituted of two distinct series of roots; one from the anterior column, and one from the posterior column, of the spinal marrow."--Henry, p. 83.

"This division comprises the first and second pairs, and the portio molis of the seventh pair."-lb. p. 91.

although exquisitely sensitive of these several things, neither of them has any sensation, any feeling from the touch. These nerves are insensible to ordinary stimulants, and possess an exclusive sensibility to their respective objectsodorous matter, light, and aerial undulation."*

The remainder of the nerves form the ganglionic system, or, according to Bichat, are nerves of organic life. These are comprised in the great sympathetic nerve, and its associated plexuses and ganglia; but the functions of these are at present matter of discussion and conjecture.†

*

I have submitted the observations and facts in this letter to your attention, in order that by studying yourself, and the origin of the knowledge and ideas which you already possess, you may perceive, and personally feel and keep in mind the grand truth, that human nature is not a casual, an undesigned, or a common or necessary course of things, or could have arisen in that way; but that it is in all respects as much intellectual as bodily, a special, a chosen, and an artificial mode of being, devised by its Creator to be so; and specifically formed and caused in every one, by a vast series and complication of specific agencies and causations, successively operating to produce the very compound and particular results which appear in ourselves and in all. It is this perception and conviction, that we are such factitious results from such special provisions purposely devised, made, and arranged, in order to cause us to be what we are, that will give us the more adequate and intimate sense of the creating mind and power of the Deity; which will most strongly lead the understanding to a due recognition of him, and to an habitual adoration and attachment to him as an indispensable REALITY; without which, such a world, and such an order of beings as ours, could not have come into existence.

* Henry, p. 91. "Magendie seems to have been the first to prove, experimentally, that they do not share the common or tactile sensibility. He found the olfactory nerves, like the hemispheres of the brain from which they spring, insensible to pressure, pricking, or even laceration. The optic nerve, and the expansion on the retina, were as insensible to stimulants. The acoustic nerve was also touched, pressed, and even torn, without causing pain."-Ib. p. 87.

† I quote Dr. Henry's report on this interesting subject, as the most concise, judicious, and correct summary of the modern discoveries on it that I have read, with a very candid statement of the claims and authenticated results of each discoverer.

LETTER X.

Considerations on the Plan and Appointment of the Creator as to the Dirision of Human kind into two Sexes--Review of the distinct Nature and Qualities of each.

MY DEAR BON,

THUS far we have been surveying some of the great principles on which human nature has been constituted, and which have been found to operate, steadily and efficaciously, to fulfil their divine Author's intentions. None have failed: they are continuing to act now as freshly and as vigorously as ever, but with more abundant results, as the human mind improves from their agency, and as our enlarging population and activity are diversifying and multiplying the objects and success of man's emulating and highly cultivated spirit. It is the operation of such principles which forms the real sucred history of the world; for this, in its incidents, only eluculates the workings of the intellectual springs and freelycombined mechanism and established powers, by which human beings are actuated, their transactions produced, and their improvements effectuated. But what we have been contemplating is only a part of the great system of our terrestrial nature. Other interesting portions of the divine plan remain to be considered, and one of the most important of these will be the subject of the present letter.

It has been appointed from the origin of our race, that it should be divided into two sexes of different temperament and character, with a corresponding distinction of powers and qualities in each. This has been made the law of the whole animated kingdom; but it is among human kind, that its moral and intellectual operations are most perspicuously displayed

This also has been a deliberate choice, and not a necessity. Each individual, like each plant, might have produced its own successor; or if there were to be two such species of human beings, each sex might have evolved a descendant Males might have had a male ancestor alone, and females one of their own kind only. Deucalion and

like itself.

Pyrrha were fabled to have thus produced the new race of mankind from the pebbles which they severally threw behind them.*

On this plan there would have been two sets of human beings, as separate from each other as eagles and pheasants are; but this mode of origin would have soon sprung up into divergences, the consequences of which we cannot calculate. One effect, however, we may say, would have ensued, that neither sex would have become what it now is. Each would have differed so much in habits, nurture, and feelings, from what they now are, and from each other, that they might never have associated in sympathy, nor have long continued in amity together.

To prevent the disadvantageous result of such a division and distinctness of origin, it has been made an unaltering principle in the divine creation of human nature, that all mankind shall be of one blood and of one descent,† with perpetually attaching sympathies thence arising towards each other; and therefore that both sexes shall be born from the same mother, and have the same father: although such an appointment required a most peculiar and complicated contrivance and creative sagacity, in order to carry it into universal and unceasing effect, through all the successions of the human duration.

Most special, indeed, must have been the devised, provisions to ensure such a perpetuated result. For that it might never fail, it has also been necessary that the two sexes should be kept alive in equal number, and therefore be born so as to preserve this mutual proportion with each other,a circumstance which the Creator made more difficult to himself by his laws of death, taking each away at all ages of their earthly existence, and by his assigning to them such different forms and offices of their bodily structure. It so happens in life, that from their more violent or consuming habits and occupations, the general mortality of males exceeds that of females. In order to prevent this consequence from altering their average equality, it became therefore ex

* See Letter XVI. of this volume, note.

† When St. Paul expressed this truth to the Areopagus of Athens (Acts xvii. 26), it must have surprised them as much as his declaration of the final resurrection, for it formed no part of the theories of any of the ancient philosophers, nor of the popular mythologies.