It was said to be the cause of the pestilential blisters of the Gulf of Bothnia. He gave it the vermiform shape, and the yellow colour of northern tradition, and conferred on it the scientific name, more ridiculous than formidable, of the Infernal Fury (Furia infernalis). Before that, at the time of the plague at Marseilles in 1721, the contagion had been ascribed to small infusory-like winged or mitelike, yet invisible, animals; and at the time there appeared in the French language many treatises, which must now appear absurd to every well-informed person. One of these, printed anonymously in 1726, to push the matter still farther, deduces all diseases from these animalcules, which are designated by the following name: Vers assoupissans, cours de ventristes, barbon quifians, clouifians, erectifs, fistulaires lacrymaux, fleuistes blancs! The tradition of the Linnean Furia still remains in Finland, where the anthrax is common; and, in Siberia, I found, in 1829, on my journey with Baron von Humboldt, a similar tradition regarding the cause of the Siberian pestilential boil, only that it was ascribed to flying large insects, without, however, one of them ever having been exactly characterised or even taken. Although we passed through many places infested with the pest, and I neglected no opportunity of learning the causes of the disease, I found no trace of this insect.

A similar tradition gave rise to the question which was put to Dr Hemprich and myself, in the year 1823, by the Pacha of Egypt, whether it was true that, in Dongala, there were flying scorpions which produced mortal wounds, for the troops refused to march there, having already suffered much from those without wings. As during my natural history researches for nine months in Dongola, I had found nothing which justified this belief, except the troublesome small mosquitoes, which were neither poisonous, nor scorpions, the mind of the Pacha was set

at ease.

As was to be expected, the same idea of invisible poisonous insects was transferred to the contagion of cholera; yet it is hardly credible that Hahnemann, as stated in the Leipzic Journal, should have for this reason recommended the sedative effects of camphor, because it killed these insects, and so expelled the cholera.

I have, for many years, made these minutest of organic bodies the subject of my particular inquiries, and have for that purpose employed the best instruments. But none before me, nor have I myself, ever succeeded in finding in the air these small bodies to which tradition had given a real existence. must, therefore, warn medical men from modes of treatment of cholera founded upon this principle, for no naturalist has yet observed these animalcules. I have never observed these animalcules under the microscope, at the time of the plague in Egypt and Siberia; and previous to my African journey, in the Hospital of the Charité at Berlin, I had examined with the microscope many contagious cutaneous eruptions, without having ever seen them. While, by the most rigorous microscopic accuracy, I have made the singular discovery, that infusory animalcules, from th tooth of a line in size, possess an organization similar to many of the higher animals, and have demonstrated their propagation by eggs and internal organs, which are less than 30th of a line, or 30th of an inch in diameter, and are yet distinctly visible.

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What must, then, be the size of the pest or cholera animalcules, or cours de ventristes, if they were not discernible by such instruments? The opinion is to be classed in the same rubric with the traditions and hypotheses of dragons, &c., and has at least been confirmed by the experience of no credible naturalist.

According to the observations of Professor Ehrenberg, the so called "Priestley's Matter," when it is not formed by real animals of a very different form, was by algæ; and particularly when it appears as a pellicle or cuticle, is the result of putrefaction, and only consists of the dead bodies of infusoria. It is therefore not the commencement of new formations, but the remains of dead organic generations.

On the Crystallization of Ice, and of Veins of Ice in Ice. By Professor HESSEL.

FOR some time past I have been occupied with observations on the different forms of crystallization. The crystallization of water under certain conditions, induced by artificial means, formed also the subject of my inquiries. I shall here briefly detail one of my experiments, which I have repeated frequently of late, as I reckon it not unimportant for the doctrine of veins, whose different modes of origin can, in my opinion, only be satisfactorily explained by collecting as many examples as possible of the formation of veins and vein-like masses since the commencement of historical epochs. So that we have then only to inquire whether, this or the other vein, or assemblage of veins, bears most resemblance to lava-veins in lava, to veins which may be considered as canals filled up by mineral springs of some sort or other, to fissures filled by sublimations, to fissures which have been the outlets for alternate streams of fluid or elastic matters, and which have been gradually closed by the deposition of solid matters, or to fissures which have been filled by infiltration from above, &c.; or whether these veins are to be viewed as the result of the contemporaneous congelation (crystallization) of two or more heterogeneous masses, one of which has filled fissures in the other, but which have never been in reality open.

Upon this supposition every experiment on the origin of veinlike masses, however insignificant it may appear, must be considered as an augmentation of our resources for the elucidation of the origin of those veins which have not been observed by man, so that this communication is of interest not merely to the crystallographer but also to the geognost.

I set aside, in a warm room, a mixture of fine clay and water, in which the latter was somewhat in excess, so that the thin mud could be easily stirred about with a fine hair-brush. Upon resting for some time it divided into two portions, the undermost of which consisted of moist clay, and the upper and least considerable of clear water. During the cold days which we had in December (5° 10° F.), I exposed the mixture after agitation to crystallization or freezing. Crystallization did not

take place till the mass had returned to the state of rest, but before the separation took place between the clay and the water. The structure of the frozen mass varied in different experiments. In every case, however, frozen mud and frozen clear water could be distinguished from each other. But the latter did not occur as a stratum at the upper part of the mass, but was distributed through the substance of the frozen mud.

1. The most common appearance was like that of small quartz veins traversing in different directions a siliceous slate. The same as in hand specimens of siliceous slate, when two of the quartz veins meet one another, they traverse one another, shift one another, or mutually cut each other off, &c. was ob served distinctly in the present instance. The principle that the traversing vein is newer than the one traversed, could not be easily demonstrated to be correct in these ice veins in the frozen mud; nor could the idea of the contemporaneous formation of veins with the surrounding rock be admitted as unconditionally correct. In these ice veins there was apparently a real cutting across of one vein by another, so that the traversed vein beyond the traversing pursued its original course, or was diverted somewhat from its position, but more frequently one was completely cut off by the other. Often we could suppose a true wedging out of such a vein without a previously existing empty fissure promoting its formation.

2. Often the water-ice was distributed through the frozen mud like the quartz in the felspar of graphic granite. The surface formed by cutting and polishing exhibiting, like the latter Hebraic, Arabic, and Chinese characters; and these were still more characterised on the dark surface of the mud, than the greyish-white quartz on the whitish felspar.

3. Another mode of distribution of the water-ice in the frozen mud, was its forming vertical plates, which were so grouped that the surface of the mass of mud on its middle section, resembled a concentrically radiated crystalline mass, the rays diverging from the centre outwards. Several of these groups of rays were observed. Each ray projected to a considerable height above the surface of the mud.

During the formation of the veins, I sometimes observed also that of hollow spaces. These were enclosed by three or more

ice veins, which penetrated obliquely downwards, partly to the bottom of the vessel; they had a breadth of from half to three quarters of an inch, and were quite empty of the frozen mud.

The frozen mud, separated as much as possible from the transparent ice, gave, when thawed, a moist mud, so that crystallization had produced no more complete separation than simple rest; but the ordinary separation of the water from the mud was produced in a much shorter time than by the mere operation of specific gravity in the mechanical mixture.

With regard to the causes of the three different appearances that I have enumerated, they appear to me to depend upon differences in the excess of water in the mud, on the temperature of the mass before it is exposed to congelation (sometimes boiling water was used), and especially the rapidity of the congelation. Farther I can give no explanation.

Account of the Introduction of the Wood-Grouse or Capercailzie (Tetrao urogallus) to the Forest of Braemar. By JAMES WILSON, Esq. F.R. S. E., M. W.S., &c. Communicated by the Author.

THE almost recent extinction in Britain of the largest European bird of the gallinaceous order, is a remarkable fact in the geographical history of the species. Its reintroduction is also a circumstance of sufficient interest to deserve a detailed record.

The wood-grouse or capercailzie, was formerly a well-known and frequent inhabitant of the Scottish forests. It still occurs in considerable abundance among the wooded and alpine districts of Europe, especially in Scandinavia. It is rare in France, well-known in Germany, not unfrequent in Switzerland. It spreads through Russia into Siberia, and is very numerous in several districts of the north of Asia. It seems always to prefer mountainous forests, and is rarely met with in plains or flat countries, however richly wooded. Its favourite trees are pines, birch, and juniper. It feeds on the fruit of the last-named plant, and on the buds and tender sprays of the two former. Colonel Montagu found the crops of two females which he examined, to contain a species of berry similar to the cranberry, called in Norway Tytteboer; and the tops of that plant, toge

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