Imágenes de páginas

The gelatinizing mass in proportion , The undecomposed Basalt, = 067,47:1 to that which did not gelatinize, The decomposed Basalt, 031,10.1

100 parts of the gelatinizing mass of the undecomposed basalt contains

[ocr errors][merged small][merged small][merged small]

The portion which did not gelatinize exhibited a peculiar composition ; but the analysis must be repeated, as the loss is so considerable :

[blocks in formation]

The quantity of alkali is remarkable, and it might be supposed that it was acquired in consequence of the silica in the gelatinizing portion being separated from that which did not gelatinize by the carbonate of potash; but that cannot be the case, because the powder was first of all acted upon by diluted muriatic acid, and then carefully washed.

The result of the investigation of the decomposed mass was, that the quantity of silica, titanium, lime, magnesia, and the alkalis was diminished, while that of the oxide of iron was considerably increased.

Chrome has been found in all analyzed basalt ; without doubt it is contained in olivine, and perhaps the chromate of iron is likewise to be found. Professor Bugengeiger of Freyburg has long since discovered chrome by means of the blowpipe.

Nothing was discovered after repeated experiments with muriatic acid, nor with sulphuric acid. Lithia has not been discovered. Strontian was by no means always found; but it was decidedly discovered in the basalt from Stetten.

On the Cholera Animalcule.

It is a very generally diffused opinion, although supported by no positive facts, that those animated creatures belonging to the lowest classes to which, on account of their minuteness, the name of Microscopic Animalcules has been given, are formed by the simple aggregation of the so-called organic molecules; and Dr Hermann has endeavoured to explain the contagious nature of cholera upon this supposition. As similar views have been more than once suggested, and it is to be feared that their plausibility may gain for them a more extended credence; the opinion of a naturalist deeply versed in microscopic inquiries, and who has personally observed the oriental plague, a disease not dissimilar in some of its characters to cholera, merits consideration. Professor Ehrenberg, in a late fugitive piece, has expressed himself in the following terms upon this subject.

To the doctrine of the similarity of the contagion of plague and of cholera, is connected with another which has lately found its

way into the public journals, and which is merely a revival of the old and antiquated idea of small invisible insects which generate this contagion by their irritation, poison, &c., and propagate it by their increase and migrations. Similar stories are to be found in the traditions of various people as well as those of the poisonous look of some human faces, of the dragon, of witches, magicians, the second sight, &c., formerly so seriously believed, but now only thought ridiculous. Linné, the great reformer of natural history, first took this fabulous animalcule into the domain of natural history, probably only with the view of directing the attention of naturalists to the subject.


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 per

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, în 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. I 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 Ith to googth 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 38 booth of a line, or 1300ooth of an inch in diameter, and are yet distinctly visible.

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.

Professor HESSEL.


[ocr errors]

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 (5o - 10° F.), I exposed the mixture after agitation to crystallization or freezing. Crystallization did not

« AnteriorContinuar »