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of Cologne, is in possession of one of the best specimens, which, as we hear, is to be sent to the Antiquarian Museum of Bonn. ( Cologne Gazette, June 21, 1863.)
Colonies and Climate—a Prophecy. Extracts from a review of works on Public Hygiene, British and Foreign Medical Review, 1 842. —" We behold the British race peopling alike the western and southern hemisphere, and can already anticipate the time when two hundred millions of men on the shores of the Atlantic and in the isles of the Pacific, will be speaking our language, reading our authors, glorying in our descent." (The Principles of Population, etc. By A. Alison, 1840, v. ii, 348.)
Need we say that the responsibility of British statesmen and of the British nation, is most solemn? In two or three centuries a larger population than exists in the whole of Europe will curse or bless us according as we have given a bias for good or evil to their infant institutions. . . .
Taking a practical view of the high questions started, we should doubt much as physiologists, whether any system of public hygiene could effectually resist the influence of an enervating climate on man, or modify the thick neck and broad jaws of the Mongol so indicative of his destructiveness. It seems to us that the customs and habits created by climate induce changes in the cerebral organization of nations, as well as in the muscular and osseous formation, and that the mental and corporeal qualities which result from these changes becoming hereditary characterize the race.
Climate will, undoubtedly, change the character of the English race. It changes it in India; it is changing it in the United States, and in less than a century will dissolve the union.* It is of importance, then, in marking the limits of new colonies, to consider the ultimate effects of climate, and place natural boundaries between them.
When the United States separate, the northern will coalesce with the Canadas, and these unitedly will constitute the dominant empire of the western continent, and perhaps of the world. These changes will hardly take place without wars, and the length and destructiveness of these wars will depend considerably upon the nature of the boundaries, and the compactness of the territories to be defended. Portions of our empire in India might be garrisoned by colonies. The climate of the high lands in Central Asia so nearly resembles our own (as do also the inhabitants themselves) that Englishmen would not deteriorate there; and would do more for the civilization of Asia and the glory of England, than the innumerable colleges and missionaries in Hindostan.
* It must be remembered tbat this was written more than twenty years ago.
ON CEREBRAL PHYSIOLOGY.
No subject is perhaps of more importance and interest to the anthropologist than the researches which are made in ascertaining the functions of the encephalon. The progress made in cerebral physiology generally, will occasionally come under our review; and the approaching publication of a translation of the works of M. Gratiolet, and of Dr. Louis Buchner's Kraft unci Staff, will compel us to examine more minutely what is the exact state of our knowledge on this subject. In the meantime, we present our readers with a sketch of our present knowledge on some of the chief points of cerebral physiology, reserving some critical remarks until a future occasion.
Chemical Composition of the Brain. The investigations of Baron Bibra ( Vergleichende Vntersuchungen, etc., Mannheim, 1856) on the chemical composition of the brain of man and the vertebrata, led to the subjoined results. Bibra had always been of opinion that, though the physiological function of the brain did not altogether depend on its fatty constituent, yet that it was mainly conditioned by it. Experiments supported that opinion. Fat is an integral constituent of the brain, being closely connected with its functions, and does not perform the same office in the brain as in other parts of the organism. Even in diseases producing the greatest emaciation, the fat is not sensibly diminished in the brain. The average quantity of fat in eleven adult brains up to 48, amounted to 14-44 per cent. The medulla oblongata always contained most, the thalami opiici and the corpora striata contained least fat. The average quantity of fat in six brains of very old men was but 13-13 per cent. Average quantity of water, 75'66 per cent. Generally speaking, those parts which have most fat have least water, and vice versd. The average of the
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solid albuminous part amounted to 10-83 per cent., somewhat more than in young individuals, in whom it was 10 09 per cent.
From the circumstance that, after any laborious mental exertion, there are frequently found in the urine large quantities of phosphatic salts, coupled with the alleged fact that in the brain of the adult idiot the quantity of phosphorus is not larger than in the brain of a child, it has been inferred that phosphorus plays some important part in the substance of the brain and its psychical manifestations.
With regard to the quantity of phosphorus contained in the cerebral fat, Bibra arrived at the following results: That the quantity is nearly equal in man, mammal, and bird; that it neither is above the average in the brains of lunatics, nor does it vary much in advanced age. There is, however, more phosphorus in the grey than in the white substance. The quantity of phosphorus seems to depend on the quantity of cerebral fat. Bibra does not think that the quantity of phosphorus is relative to greater or lesser intelligence; though it is certain that the brains of higher animals contain a larger amount of fatty matter, and consequently a larger quantity of phosphorus. The fat has, no doubt, a physiological function as a whole; but it does not follow that the phosphorus specially influences the brain in its intellectual function.
It has been already stated, that the diminution of fat caused by wasting diseases in other parts of the organism does not extend to the brain. Fattening of animals does not increase the amount of cerebral fat. The human brain contains more fat than that of mammals, and the brain of mammals more than the brain of birds. The quantity of cerebral fat is rather less in old than in healthy adult individuals. The brains of mammals cannot be said to contain more water than the human brain; it seems that the lesser quantity of fat is replaced by a larger amount albuminous substance. The brain of birds contains a larger amount of water than that of man and mammals.
Cerebral Circulation. Considering that the brain is not merely the organ of the mind, but the source of energy of a considerable portion of the body, and consequently itself subject to great wear and tear, we might d priori assume that a large supply of arterial blood was •requisite for its nutrition. And such is actually the case; for this supply is estimated at not less than one-fourth of the whole quantity of blood in the body, which reaches the cranium by four independent channels, derived from the chief trunk of the aorta, namely, the carotids and the vertebral arteries. The force with which the blood is propelled by the left ventricle, may be estimated when we know that after decapitation the blood is projected from the carotids to a distance of five or six feet. But so delicate is the structure of the encephalon, that a circulation through the nervous tissue, in the mode as carried on in other organs, would be incompatible with its functions; hence the division of the large arterial trunks before they enter the brain.
Until a recent period, there prevailed an opinion that the quantity of blood within the cranium was constantly the same. The chief argument in favour of this theory was, that the cranium is a closed hollow sphere, with unyielding walls, filled with fluid. But the cranium is neither altogether unyielding, nor a closed cavity, being, as now proved, connected with the cavity of the spinal canal. Besides this, the cranial cavity is not filled by a simple incompressible fluid, but in addition to the brain by a watery liquid, the quantity of which is subject to constant changes, owing to resorption or secretion, and to afflux or reflux between cranium and spinal canal. Owing to this, and a variety of other circumstances, an expansion or contraction of the cerebral blood-vessels, and consequently an increase or diminution of blood within the cranium, is not merely possible, but must actually occur.
Cerebro-Spinal Fluid. Physiologists differ as to the importance and functions of this substance. Some have considered it as a post mortem phenomenon. This is now proved an error, as experiments on animals have abundantly shewn. Magendie, who was one of the first who called attention to this fluid, estimated its average quantity in the adult subject at sixty-two grammes; which Dr. J. Williams (Lancet, 1860) considers much below the average. "The clear fluid," observes Dr. Williams, "which sometimes escapes from the ear and nose in cranial fractures, is now proved to be the cerebro-spinal fluid." According to Magendie, the evacuation of this fluid very frequently plunges even the most vigorous animal into a state of complete inertia; and that any change in the quantity or quality of that substance produces well-marked disturbance in the animal economy.
According to Ecker (Physiologische Untersuchungcn, etc.—Physioh' gical Researches in.the Cerebro-Spinal Fluid, 1843), the cerebro-spinal, liquid is in constant motion, especially during inspiration. It is accumulated between the arachnoidea and the pia mater; it flows during inspiration into the fourth ventricle, and then through the aquaductus Sylvii into the third and the two lateral ventricles. This fluid has been found in considerable quantity in the section of para
lytics. It cannot d priori be denied that its accumulation in the ventricles may disturb motion. "Perhaps," observes Ecker, "it is owing less to the increase in the ventricles than to its simultaneous diminution in the other parts of the periphery of the hemispheres of the brain and cerebellum. Removal of this fluid in animals by an aperture between the atlas and skull made animals lose their equilibrium; spasms and tremors occurred in the extremities; all which phenomena disappeared on the renewal of the liquid. It is clear, therefore, that the cerebro-spinal liquid is not merely a conservative provision, but influences both physical and psychical phenomena." The pia mater seems evidently the organ which secretes it from the blood on the surface of the nervous centres, and it then passes, by a mechanism unknown to us, into the cavities of the brain. Salt, introduced into the current of the circulation, a portion of the substance is soon found in cerebro-spinal fluid. In an inquest on Sam. Page, who died from excess of spirituous liquors, Dr. Bradley of Boston (U. S.) found on dissection a strong alcoholic odour in the fluid in the ventricles, recognized by every one of the jury. (Amer. Jour, of Med. Science.) The cerebro-spinal fluid favours the movements of the brain, and prevents any friction of so tender a body as the nervous pulp against the parietes surrounding it.
The long-pending question about the existence of a central canal in the spinal cord, and the fact of the intercommunication of the subarachnoid spaces, have been set at rest by the anatomical investigations of Luschka (Die Adergeflechte, etc.—The Venous Plexuses of the Human Brain, 1855). The spinal canal communicates above with the fourth, or, as Luschka calls it, the ventricle of the cerebellum, which again opens into the sub-arachnoid space through an aperture at the end of the calamus scriptorius.
The celebrated German physiologist T. Ch. Reil, in whose works many of the germs of apparently recent physiological discoveries may be found, had already conceived the plan of an anatomico-physiological comparison of the cerebral structure and mental activity of animals with that of man, with special reference to race, nation, sex, and age, both in the healthy and morbid state. The following invocation, preparatory to his dissecting a human brain, is so characteristic of this enthusiastic physiologist, that we have no hesitation in quoting it. "Direct my hand, Erato! that I may gently open the shell which covers the noblest production of creation. Arm my eye with acutencss, that it may intelligently examine the Daedalus of organization, which is the birthplace of history, the cradle of art, and