cient freedom to allow of distinct vision. On the contrary, if the pupil were permanently dilated, we might take advantage of the scattered rays of light, but should be distressed and blinded by the glorious effulgence of the sun.

The ball of the eye is filled with three substances, which differ from each other in consistence, but are all called humours of the eye; they are the aqueous, vitreous, and crystalline.

The aqueous or watery humour, which is a perfectly limpid fluid, fills the space between the iris and cornea, or the anterior chamber of the eye. Its use appears to be to distend the cornea, and preserve its convexity: it likewise affords a medium for the iris- to float in, so that it may perform its motions with perfect freedom. The watery humour accordingly fills the opening of the pupil, and a small quantity of it also lies behind the iris. The portion of the eye behind the iris is much the larger one, and is chiefly filled with a transparent fluid, which, from its appearance, is called the vitreous or glassy humour; resembling very nearly melted glass, or the white of an egg. There is, besides, a small round transparent body, set in the front of this humour, like a diamond in a ring, immediately behind the pupil. This is the crystalline humour or lens. The glassy humour does not float freely like the watery, but is contained in a very transparent membrane, which is so arranged as to form innumerable little bags, each one containing a drop of the fluid, and so perfectly transparent as not to break the course of a single ray of light. The uses of this humour would appear to be, to keep the ball of the eye distended to the size necessary for the purposes of vision, and to retain the crystalline lens at the proper focal distance. This latter body, as has been already mentioned, is placed immediately behind the pupil, in a cup-like depression of the glassy humour. In form, it is like a very small, thick spectacle glass, or the doubly convex lens of a spy glass. It is composed of very transparent scales, laid one over the other. In the centre of the lens, these scales lie closer together than they do nearer the surface, forming a kind of firm button, which will leap out if the outer scales be divided. The whole lens is surrounded by a strong, thick, transparent and elastic skin or capsule. The use of the crystalline lens is to concentrate the rays of light, proceeding from objects in the field of vision, so as to form a distinct image of them at the bottom of the eye upon the retina, or nervous coat. From this last, through the medium of the optic nerve, the image is conveyed to the brain.

The lens becomes occasionally opaque, constituting the disease termed cataract. Sight is of course prevented, and on looking into the pupil, it is perceived to be cloudy, gray or white, and not deep black, as in the healthy eye. The foregoing description

will be better understood by the following drawing, which represents a longitudinal section of the eye ball.

PROXIMATE PRINCIPLES OF VEGETABLES.

A BRIEF Summary of the nutritive elements of vegetable bodies will, we have reason to believe, be acceptable to our readers, and prepare them for a better understanding of the subjects of aliment, and nutrition in general.

Every distinct compound which exists ready formed in plants, is called a proximate or immediate principle of vegetables. Thus sugar, starch, and gum are proximate principles. "The proximate principles of vegetables are sometimes distributed over the whole plant, while at others they are confined to a particular part. The methods by which they are procured are very variable. Thus gum exudes spontaneously, and the saccharine juice of the maple tree is obtained by incisions made in the bark. In some cases, a particular principle is mixed with such a variety of others, that a distinct process is required for its separation. Of such processes, consists the proximate analysis of vegetables. Sometimes a substance is separated by mechanical means, as in the preparation of starch."*

The chief nutritive principles in vegetables, are gluten, starch or fecula, sugar, gum, and oil, on the quantity and different preparations of which depend their alimentary properties. The first of these principles may be exhibited in the familiar process of making starch from wheat flour. Thus, if we take a paste of moistened flour, enclosed in a piece of linen, and pour water on it, this fluid carries off a part of the flour, and leaves, by repeated washings and squeezing between the fingers, nothing behind but a tenacious mass, called gluten. The water has carried off the fecula or starch, which gradually falls to the bottom of the vessel, and a small proportion of sugar and gummy matter which are dissolved in it. The difference in the nutritive properties of grains and esculent roots is explicable, as we have just said, by the various proportions of these proximate principles. In many of the nut tribe, oil is the most abundant principle. In the following table, the figures are expressive of so many parts in the hundred.

Starch or fecula. Sugar or sweet matter. Gum. Water.

Wheat,

Barley,

Rye,

Oats,

Rice,

Potatoes,

72 to 75

10 to 15

nearly all
nearly all
nearly all

70 to 80%

Turner's Chemistry-edited by Franklin Bache, M. D. Philadelphia, John Grigg.

Davy makes the proportion of gluten in wheat, to be from 19 to 24 per cent. whilst Vauquelin and Henry, of Paris, find the flour of the Paris bakers to be 10.20 to 10.25 per cent. The difference, therefore, is very great in the varieties of wheat.

The reader who is aware of the nutritive properties of the potato, will be astonished at the small proportion of fecula which it contains, and also at this being the only proximate principle of an alimentary nature. There is another principle, the woody fibre, or lignin, in the potato, which is in a great measure insoluble in the stomach: it is found in the proportion of from ten to fifteen per cent. In these experiments, the potato is supposed to have *been peeled.

In the proximate analysis of barley, chemists discover a peculiar principle, called hordein, in the proportion of fifty-five per cent.; but it so nearly resembles fecula that we have classed it under the same head with this latter, which, pure, is represented as constituting thirty-two per cent. of this grain. For the same reason, we have represented sago and tapioca as consisting nearly all of fecula or starch, whereas, in rigid chemical classification, it should be amidine, or starch modified by dry heat or by boiling water,

The detailed properties of these several proximate and nutritive principles will form the subject of future notices.

HISTORY OF THE INDIAN CHOLERA.

THE epidemic cholera, which is now prevailing throughout the north of Europe, adding the horrors of pestilence to those of war, has become a subject of deep interest to every portion of the civilized world. However remotely situated from the present theatre of its ravages, there is no country the inhabitants of which can flatter themselves that they are perfectly secure from its visitation. Travelling, as it does, with an unexampled rapidity; unarrested in its progress by mountains or seas; prevailing alike in the driest weather and during the deluge of periodical rains; in storms and in calms; under the scorching sun of Arabia and amid the frosts of Russia, to determine the point or period at which its further extension will be stayed, defies all human calculation. Commencing at a point almost the farthest removed from ourselves, it has already traversed nearly half of the mighty interval, and, however improbable it may appear to some, that the disease will ever extend across the Atlantic; yet, judging from its progress heretofore, and the space over which it has already passed, this is by no means impossible. The only certain means of preventing the cholera from extending itself to this country, are a timely resort to correct precautionary measures founded upon the nature of the disease and the general principles of hygiene. With this fact in view, we have conceived it to be our duty to lay before our readers a brief sketch of the rise and progress of the pestilence, and, so far as we are able, from the documents in our possession, some account of its character and causes, together with the proper means for its prevention.

The terrific epidemic which is now ravaging the immense districts of the Russian empire, commenced its destructive career in various parts of the delta formed by the Ganges, during the summer of 1817. In 1818, it had reached as far north as Saharunpore, high up on the Jumna, and extended

itself south to Cape Cormorin, its westernmost limit being at Bombay and Surat, its easternmost at Sylhet: spreading towards the interior, from the mouth of the Ganges to its confluence with the Jumna, it extended itself over a space including four hundred and fifty square miles. In 1819, it attacked the Isles of France and Bourbon, in twenty-one degrees of south latitude. In the latter island, it began early in December. Of two hundred and fifty-seven persons seized with the distemper, one hundred and seventy-eight died. In 1820, it ravaged Siam, Malacca, Java, the Philipine Islands, the southern provinces of China, and Guzzerat, in India. In 1821, it is said to have destroyed sixty thousand subjects of the prince of Oman, round Muscat: during this year, it reached Bahrein, Bassora, Bagdad, Bushire, and Shiraz. In this latter city, the population of which is forty thousand, there died sixteen thousand in the first few days. In Bassora, eighteen thousand individuals perished, of whom fourteen thousand died in two weeks. During the succeeding winter, the disease became dormant, both in Persia and Syria. In 1822, it spread to Ispahan, Teheran, and Tabriz, to Diarbekir and Moussul, and reached, in 1823, the island of Amboyna, in one hundred and twentyseven degrees of east longitude, extending also to Antioch, in longitude thirty-six degrees, and to Astrachan, in Asiatic Russia, in latitude forty-six degrees north. Having spread, in seven years, over ninety-one degrees of longitude, from Antioch to Amboyna, and sixty-seven degrees of latitude, from the Isle of Bourbon to Astrachan, and destroyed, in its course, not less than six millions of human beings.

The disease is generally understood to have broken out first at Jessore, a city eighty or ninety miles north-east from Calcutta, in the middle of August, 1817; but it appears to have prevailed to a considerable extent in the district of Nuddea, west of the Hoogly, as early as May and June. In July, it appeared also at Patna, near three hundred miles directly north-east of Calcutta. In the first week of August, at Calcutta, at Dacca, and Dinapore; on the 17th, at Sylhet and Jessore; by the end of August, at Boglipoor and Monghyr; September 15th, at Balasore; 17th, at Buxar; 18th, at Chupra and Ghazeepoor, and, by the end of November, at Rewah and Cuttach; the two last places being separated by at least four hundred miles. The causes of the disease appear to have been in a languishing or quiescent state during the winter of 1817; but in the months of April and May, 1818, they were manifested again with extreme violence, not only in many of the places where the disease had already appeared, but also at Ougein, Hooshungabad, Nagpore, (with numerous intervening districts,) and Ganjam; all these being nearly on a line of six hundred and forty miles from north-west to south-east. In various other places on a line, north and south, of six hundred miles, from Goruckpore to Visgapatam, the disease was also prevalent during the same period, of the year 1818. The cholera appeared in the latter year, in its most malignant form, at Benares, where, in two months, fifteen thousand persons perished. At Allahabad, forty or fifty died daily; and in the district of Goruckpore thirty thousand were carried off in a month. Between the 6th and 7th of November, the epidemic had reached the grand army of India, which, on the approach of the Pindarree war, had been concentrated at Jubbulpore,

Mundellah, and Sauger, under the command of the Marquess of Hastings. It consisted of ten thousand troops and eighty thousand followers. To the different divisions of this force the cholera proved more fatal than could the shot of the enemy in a well contested field. In twelve days, nearly nine thousand men had fallen to rise no more. In this emergency, it was fortunately determined by the commander-in-chief to try the effects of a change of location. The division accordingly moved in a south-easterly direction. In a short period, the Marquess was enabled to transmit a despatch to government, intimating that, having marched fifty miles, he had at last fixed upon a dry and elevated soil, where the pestilence rapidly declined.

Cochin-China and Tonquin were visited by the cholera in 1820. In December, of this year, it entered China, beginning its ravages at Canton.— Pekin admitted the enemy in 1821, and, during this and the following year, the mortality was so extensive that coffins and other funeral requisites were necessarily furnished at the expense of the public treasury, for the interment of the poorer classes. Numbers of people, engaged in the pursuits of business or pleasure, riding or walking, were seen to fall in the streets, exhausted by the sudden impression of the disease, which carried them a few hours afterwards to eternity. In many instances, the disease caused instantaneous death. Mr. Gordon relates many cases of this kind. At Bellary, a tailor was attacked with the cholera, and instantly expired, with his work in his hands, and in the very attitude in which he was sitting.

The rapidity by which the progress of the cholera was marked, may be judged of from the following statements. In less than a month, it spread from Jessore to Calcutta, a distance of nearly one hundred miles. From Jessore it reached Bombay, a distance, say, of eleven hundred miles, in twelve months, travelling at the rate of about three miles per day! It went from Allahabad to Etawah, at the rate of five miles a day; from Etawah to Agra, at the rate of about two miles. In its course across the Deccan, it advanced, in many instances, at the rate of fifteen to eighteen miles a day. The pestilence did not spread itself at once over a large extent of country, but attacked different places in succession; travelling, as it were, by a chain of posts, and attacking a second district, after it had ravaged a first.

With these details of the progress of the disease, in India, we must close on the present occasion, intending, in our next number, to trace its entrance into the Russian empire.

Pennsylvania Temperance Convention.-On the 24th of August, a Convention of delegates from several Temperance Societies in Pennsylvania, assembled at the Court House, in Harrisburg, Twenty-eight delegates, representing seventeen societies, attended. Delegates were also appointed by the Washington county, Fayette county, Butler county, and Reading Temperance Societies, who were prevented from attending by unavoidable circumstances. The Convention was organised, by appointing ROBERTS VAUX, Esq., of Philadelphia, President, and R. N. HAVENS, of Pittsburgh, and RICHARD T. LEECH, Esq., of Harrisburg, Secretaries. After transacting the business for which it had assembled, the Convention adjourned on the evening of the 26th.-The Governor, Secretary of State, Surveyor General, and Auditor General took seats in the Convention.

THE JOURNAL OF HEALTH, is published at the Literary Rooms, No. 121 Chesnut street, Henry H. Porter, proprietor, on the second and fourth Wednesdays of every month. The subscription is $1.25 per annum, payable in advance.-The first and second volumes can be had, as above, in boards or bound.-The postage on each number of the Journal is the same as on newspapers.