men to live to so great an age, or that men in general lived at any time longer than at present: indeed, we have strong reasons to believe that mankind live longer now than formerly; in England, at least, this is undoubtedly the case. The salubrity of England has considerably increased, and the mortality diminished, for many years past. The results of the population-acts afford satisfactory evidence, that our ancestors did not enjoy the same degree of health and longevity that we do at present. The annual mortality has decreased nearly one-third in forty years. In 1780, the rate of mortality was taken at one in forty; in 1795, at one in forty-five; in 1801, at one in forty-seven; in 1811, at one in fifty-two; and in 1821, the results of the census shew a mortality of one in fifty-eight. The limits of human life are the same now as formerly, and will probably always continue the same, but more persons live now to an advanced age than in former times.

Man is by nature a mortal being, and it is not in the power of art to make him immortal; yet art has done much in preserving and restoring his health, and in increasing the duration of his life. Various have been the measures that have contributed to produce these effects; the principal of which are, the improvements that have been made, in modern times, in our food and clothing, in the cleanliness of our houses and towns, in the drainage of the country, and in the treatment and prevention of diseases. This country has become more favourable to health and longevity, since more attention has been paid to the cleanliness and ventilation of our houses and large towns; and since warmer clothing, and a more nourishing and more easily digestible diet, have been employed. Some of the most formida ble and fatal diseases that prevailed in former times are now either extinct, rarely met with, or much mitigated in their violence; such as the plague, dysentery, scurvy, malignant, intermittent, and remittent fevers, and smallpox. A few diseases, it is true, have lately become more frequent and fatal; such as consumption and apoplexy, but these not being infectious, like some of the others, are of much less consequence.

On reviewing the various instances of longevity on record, it appears, that the circumstance most necessary to secure long life, is to be born of parents who enjoy good health, and are predisVOL. X. NO. 19. JAN. 1824.

I

posed to live to a great age. Children, it is well known, frequently inherit the constitutions and diseases of their parents. Many persons, who have attained to extreme old age, were born of parents who were themselves long livers; which renders it highly probable, that longevity is in a great degree hereditary. The next circumstances, most conducive to health and long life, are plain wholesome diet, temperance, warm clothing, and regular exercise in the open air. Very few persons who are intemperate and irregular, or lead an idle and sedentary life, possess good health, or ever attain to advanced years.

CARLISLE, May 1823. J

ART. XX.-Notice respecting some New Electro-magnetic PheBy Major-General BARON VAN ZUYLEN VAN

потепа.

NYEVELT *.

IN a former number (Vol. IX. p. 167.), we have laid before our

readers an account of the Electro-magnetic Experiments made by Baron Van Nyevelt, Professor Moll, &c. In pursuing this inquiry, the first of these philosophers has found that he can produce very decided effects on the inclination or dip of the magnetic needle, by means of the simple apparatus which we have already described +.

In order to produce this effect, the strips of metal, instead of being placed the one above the other, as in the experiments already referred to, are placed the one alongside of the other, but at such a distance as to leave sufficient room for the dippingneedle to be placed between them. In order that the electromagnetic action may be the same throughout the whole length of the needle, the strips of metal are placed on the angle of inclination, by placing the whole apparatus in the direction of the magnetic meridian.

With this apparatus Baron Van Nyevelt obtained the results given in the following Table.

p. 274.

Abridged and translated from the Bibliotheque Universelle, August 1823,

See Vol. IX. of this Journal, Plate IV. Fig. 7-15.

Observations. In these results, no notice is taken of the contacts with the same metal, the effect being merely increased in proportion to the quantity of surface exposed to the liquid.

When the two ends of the strips are united under the acid, the effect is diminished in the first four of the preceding apparatuses, and destroyed in the last six apparatuses.

ART. XXI.-Observations on the Anatomical Structure of the Cassowary of New Holland (Casuarius Novæ Hollandiæ, Cuv.) By ROBERT KNOX, M. D. F. R. S. E *.

AN opportunity having occurred to me lately, of examining,

though in a cursory manner, both species of Cassowary at present known, viz. that found in the Indian Islands, and long since described under the name of the Galeated Cassowary, and the species lately discovered in Australasia, and generally distinguished by the name of Emeu Casuary, some remarkable differences in the internal structure presented themselves, confirmative of an opinion already formed by naturalists, that these birds constitute distinct species. I shall limit myself to a very brief notice of these differences, as well because the specimens were greatly mutilated, and the time allowed for the dissection (owing to the weather) very short, as likewise because leisure is wanting to enable me to become acquainted with the dissections of the same species of birds which may have been performed by others.

On referring to the Systema Natura of Linnæus, I find that the Emeu of New Holland was unknown to him. It is slightly mentioned by Professor Blumenbach, in his Manual of Natural History, as a new species lately discovered in New Holland, but it is not described. The compilers of the " Dictionnaire des Sciences Naturelles," describe the bird at some length, as being a new species, quite distinct from the Galeated Cassowary or Struthio Casuarius of Linnæus. No mention is made of the internal structure in either bird. The "Regne Animale" of Baron Cuvier describes these birds as forming two distinct species, and which might even be considered as genera. They are characterized by the names of Struthio Casuarius and Casuarius Nova Hollandiæ. No mention is made of the internal structure in the latter. Finally, in the celebrated " Leçons d'Anatomie Comparée," one species only is mentioned, viz. the Galeated Cassowary.

After this very brief notice of the history of these birds, I shall proceed to compare their internal structures. The carcases, in both specimens, were extremely fat, and the abdominal cavity remarkably so. They were females. The galeated cassowary had

* Read before the Wernerian Natural History Society, 26th April 1823.

died of inflammation of the lungs and air-cells in the bottom of the neck. The investing membrane was excessively vascular; and the lymph, effused over a very extensive surface, had assumed, as is usual, the form of a membrane. There was little or no effusion. The cause of death did not appear on the dissection of the New Holland Cassowary. It will be readily imagined, that I did not even attempt to look at the nervous system, since the only parts which came properly under my inspection were the viscera, cut from the back-bone, and dragged out through the abdominal cavity.

Of the organs of sense, the only one I had it in my power to examine was that of vision. Many interesting appearances presented themselves, to detail which would be foreign to the object of this notice, and would, moreover, interfere with a me moir I am preparing on the anatomy and physiology of this organ. I shall therefore merely mention, that the examination of the eye in the Galeated and New Holland Cassowary, confirmed all my previous observations on the eyes of birds, the principal of which go to prove, that the marsupium, by some considered a muscle, is simply a membranous expansion reflected by the choroid, and quite continuous with it; that the white lines of nervous matter at its base, to which so much importance has been attached by some, are occasioned by the dissection, and are not natural to the organ; that there is a perfect analogy between the marsupium in birds and in many fishes; that the annulus albus, or ciliary ligament, supposed by some distinguished anatomists to be a nervous plexus or ganglion, is a muscular body, and is principally concerned in enabling the eye to adapt itself to the perception of objects placed at various distances.

The salivary glands have been already sufficiently described. The tongue, in each, is small, triangular, and has on its edges a number of soft projecting fringe-like bodies. The hyoid bone is also small, corresponding with the dimensions of the tongue, and with its comparative immobility. A true membranous crop can hardly be said to exist, since the gullet dilates uniformly until its termination in the ventriculus succenturiatus or glandular crop. This latter is divided, as in the ostrich, into two portions, viz. one possessing glands, and one without apparent secreting organs, placed between the former and the gizzard. The por