The following additional new facts respecting paraffine are worthy of record :

A New Use for Paraffine.-Every chemist has experienced the annoyance of finding the stopper of his liquor potassæ bottle hard set. Greasing the stopper would only afford a partial remedy, and, moreover, would be objectionable chemically, inasmuch as the liquor potassæ would suffer contamination. Paraffine is unobjectionable; not only does it not dissolve in alkaline leys, but its lubricating properties are sufficient to prevent all jamming of the stopper.

Mr. Herapath, of Bristol, in a letter to the Times, writes :— "So many accidents have occurred from the explosive character of an oil that has been sold as paraffine or petroline, that I think it advisable to make the public acquainted with an easy method of proving whether the oil is dangerous or not. Let two or three drops of it be allowed to fall upon a plate or saucer, and apply to them a lighted match; if the flame spreads over the surface of the drops the oil should on no account be used, as it will under many circumstances prove explosive. The genuine paraffine or petroline will not burn except upon a wick."

In a valuable article on Photogen, by Mr. Greville Williams, in the last edition of Ure's Dictionary, is a table showing the materials employed for distilling the oils, with the per-centage of tar and of the oils and of paraffine. The raw material consists of Trinidad pitch, the bog-head coal, and torbane mineral of Scotland, Dorset shale, Belmar turf from Ireland, George's bitumen from Neuwied, paper coal and brown coal from various parts of Germany, and Rangoon tar. But of all the substances hitherto employed none are so rich in results as the last.

The death of two persons from an accidental ignition of paraffine oil has again raised the question of its inflammability. In the report of the inquest, it is stated that the oil is not inflammable without a wick, and that it cannot be fired by dropping a light into it. The same statement was made in the month of October, 1859, when there was an inquiry before the coroner for the City into the cause of the fire at the warehouse of the Paraffine Oil Company in Bucklersbury ; but it was proved that the oil would ignite in this manner, and that this, indeed, was the actual cause of the fire in the Company's warehouse. At that inquiry the properties of the oil were carefully investigated by two chemists of eminence-namely, Mr. Warrington and Dr. Letheby, and they both declared the oil to be dangerous; Dr. Letheby, indeed, showed by experiment in court that a piece of lighted paper would fire the oil when dropped into it, and both the chemists proved that the oil gave off inflammable vapour at a temperature of 160 deg. of Fahrenheit. The result of that inquiry was that the jury declared the oil to be dangerous from its inflammability. That the discovery of the mode of manufacturing this oil, and the use of it for illuminating purposes, is a great boon to the public there can be no doubt, but in proportion to its value is the necessity for guarding against accident from it. It appears that the danger arises from two causes-namely, the leaving of a large portion of the more volatile part of the oil in it before it is sent into commerce, and,

secondly, the use of a spurious oil, which, like benzole or coalnaphtha, is highly inflammable. With proper precautions both of these sources of danger may be avoided.

CHEMISTRY OF BLOOD.

M. DENIS has communicated to the Paris Academy of Sciences a continuation of his researches. About three years ago, he extracted from Blood a substance which he has named "plasinine," because it possesses the property of solidifying without the intervention of any appreciable cause, and probably plays an important part in the economy of the living animal. He has obtained this remarkable substance from the blood of men, calves, and oxen. Its solubility in water is probably due to its containing a little common salt. When submitted to the action of alkalies or acids it becomes an albuminoid. The last fibrine, which constitutes the albuminous part of the globules of venous blood, M. Denis terms "globuline." -Comptes Rendus.

SECRETION OF THE HUMAN PANCREAS.

MR. W. TURNER has communicated to the Royal Society of Edinburgh a paper "On the Properties of the Secretion of the Human Pancreas." The author obtained the pancreatic secretion at a post-mortem examination which he made of the body of a patient of Mr. Spence, who had died with a medullary tumour in the head of the pancreas, which, by compressing the biliary and pancreatic ducts, had produced dilatation of the ducts of the liver and gallbladder, as well as dilatation of the ducts and lobules of the pancreas. The secretion was contained in the dilated parts of the gland last named, from which it was drawn off by means of a pipette. The fluid thus obtained was of an orange-yellow colour, and wellmarked viscid consistency-sp. gr. 1.0105; appearance slightly turbid, owing to the presence of small white flakes, which a microscopic examination proved to consist of groups of small spherical, colourless cells, resembling, and most probably consisting of, the epithelial lining of the vesicles of the gland. Reaction faintly, yet decidedly, acid; heat, alcohol, corrosive sublimate, and bichloride of platinum threw down copious yellowish-white precipitates, consisting of the peculiar albuminous constituent of the secretion. No reduction was effected by boiling the fluid with freshly precipitated blue oxide of copper, showing the absence of sugar or any corresponding deoxidizing substance. The absence of sulpho-cyanide of potassium was shown by no reaction being given with a solution of perchloride of iron; thus affording a well-marked distinction between the composition of the human saliva and pancreatic juice. A partial emulsionizing effect was produced by rubbing some of the fluid with a little oil. With another portion of the secretion, starch was converted into dextrine. The action of the fluid upon albuminous substances was also tested, but a negative result was obtained. It should be stated, however, that but a small quantity of

the secretion was now left, and that a day had elapsed between its withdrawal from the body and the application of this test. The author then adverted to the accounts which have been given by various physiologists of the pancreatic fluid obtained from the different domestic animals which it is usual to experiment on when samples of this secretion are required, and concluded by showing in what respect the secretion of the human pancreas agreed with, or differed from, that of these animals.

SPONTANEOUS GENERATION.

MM. JOLY AND MUSSET have sent to the Paris Academy of Sciences, further researches on Spontaneous Generation, a theory which they support. Their paper contains a description of certain new experiments of their own, from which it appears that whatever precaution may be used to destroy the germs said to float in the air, by heating it, and making it pass through concentrated sulphuric acid, and no matter how long the organized substances experimented upon have been exposed to ebullition, the vessels in which the operations have been conducted will be found to contain organized productions which cannot have been introduced by atmospheric air.

TREATMENT OF CROUP.

Dr.

In this dangerous disease, certain practitioners in France have endeavoured to rid the trachea of the false membranes which encumber it, either by mechanical or by chemical means. Ozanam has communicated to the Paris Academy of Sciences a series of numerous experiments made with different chemical agents not hitherto tried, and from which we select the following:-The chloride of potassium dissolves the false membranes completely in twenty-four hours; chloride of sodium in thirty-six; a solution of one hundredth part of bromide of potassium in water in twelve hours; a mixture of bromine and bromide of potassium is more powerful still. One part of chromate of potassium in ten of water will harden the membranes in the course of two days. The sub- and bi-carbonates of potash, in concentrated solutions, will dissolve the membranes in twelve hours. Phosphate of soda is less active; the cyanide of potassium in a concentrated state will dissolve the membranes in fifteen hours; pure glycerine will soften them in twenty-four hours; but the mother water of wrack soda will effect a complete solution in four or five hours. Dr. Ozanam concludes from his experiments that, if it be intended to attack the membranes by dissolvents, alkalies should be preferred; and from what we have quoted above it will appear that the sub-carbonate and chlorate of potash and the phosphate of soda, so long advocated, are the lowest on the list in point of efficacy. If, on the contrary, segregation or separation be aimed at, then chloride of bromine, bromine itself, and chlorine, or else iodine, perchloride of iron, and chromium, should be resorted to, since they harden the membrane, and make it detach itself. These

conclusions acquire great value from the fact that Dr. Ozanam has been pursuing these researches since 1849. He quotes a singular instance of a cure which occurred in 1860. A country physician having, in a case of croup, attempted to cauterize the false membrane by stick-caustic, the patient, somehow or other, swallowed the whole piece. In an agony of terror the practitioner forced a concentrated solution of kitchen salt (hydrochlorate of soda) do wn the patient's throat by way of antidote, and, to his surprise, not only saved him from the effects of the caustic, but also cured him of his croup by the same simple remedy.-Galignani's Messenger.

ENAMELLING ON GLASS.

M. F. JOUBERT has communicated to the Society of Arts "A New Method of producing on glass, Photographs, or other Pictures, in Enamel Colours."

For this purpose (says M. Joubert), I proceed in the following way :-A piece of glass, which may be crown or flatted glass, being selected as free from defect as possible, is firstly well cleaned, and held horizontally while a certain liquid is poured on it. This liquid is composed of a saturated solution of bichromate of ammonia in the proportion of five parts, honey and albumen three parts of each, well mixed together, and thinned with from twenty to thirty parts of distilled water, the whole carefully filtered before using it. The preparation of the solution, and the mixing up with other ingredients, should be conducted in a room from which light is partially excluded, or under yellow light, the same as in photographic operating rooms, so that the sensitiveness of the solution may not be diminished or destroyed.

In order to obtain a perfect transfer of the image to be reproduced, the piece of glass coated with the solution, which has been properly dried by means of a gas stove (this will only occupy a few minutes) is placed face downwards on the subject to be copied in an ordinary pressure frame, such as are used for printing photographs.

The subject must be a positive picture on glass, or else on paper rendered transparent by waxing or other mode, and an exposure to the light will, in a few seconds, according to the state of the weather, show, on removing the coated glass from the pressure frame, a faintly indicated picture in a negative condition. To bring it out, an enamel colour, in a very finely divided powder, is gently rubbed over with a soft brush until the whole composition or subject appears in a perfect positive form. It is then fixed by alcohol, in which a small quantity of acid, either nitric or acetic, has been mixed, being poured over the whole surface and drained off at one corner.

When the alcohol has completely evaporated, which will generally be the case in a very short time, the glass is quietly immersed, horizontally, in a large pan of clean water, and left until the chromic solution has dissolved off, and that nothing remains besides the enamel colour on the glass; it is therefore allowed to dry by itself near a heated stove, and when dry is ready to be placed in the kiln for firing.

It may be stated that enamel of any colour can be used, and that, by carefully registering, a variety of colours can be printed one after the other, so as to obtain a perfect imitation of a picture; also the borders of any description can be subsequently added, such as those shown in the specimens on the table, without any liability to remove or even diminish the intensity of the colour in the first firing.

It will be easy to perceive that this mode of obtaining an image on glass, in an absolutely permanent substance, and of any description, colour, or size, may prove of considerable advantage and utility for the decoration of private houses, and also for public buildings. Through means of the photographic art, the most correct views of any object or of any building or scene-even portraits-can be faithfully and easily obtained.

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Natural History.

ZOOLOGY.

LIMITS OF SPECIES.

THERE have been read to the British Association, "Notes on the Variation of Tecturella grandis," by P. P. Carpenter.

Prof. Williamson observed, that it was facts like those brought forward by Mr. Carpenter that were wanted to test the limits of species. Amongst the Foraminifera he had long been acquainted with the extreme difficulty of determining the limits of particular species. The Darwinian theory had made it necessary to study every individual form, so that no species should rest on characters obtained by the absence of intermediate forms. The Hon. W. Elliott pointed out the extreme difficulty of referring some of the Carnivora and Quadrumana of India to the described species on account of intermediate forms. He instanced the Viverra Tibetica and the V. Bengalensis. Prof. Babington said, that nothing could be more disastrous for science than the giving up the study of individual forms. If the Darwinian theory led to the abandonment of our present idea of a species, it ought to lead us to be much more exact in the study of individual forms.

ETHNOLOGY AND PHYSICAL GEOGRAPHY.

MR. J. CRAWFURD has read to the Ethnological Society a paper "On the Connexion between Ethnology and Physical Geography," in which he pointed out the constant relation met with in the barbarous or civilized conditions of the races of man in proportion to the quality of the race and the physical character of the country to which it belonged. Mere intemperance of climate was sufficient to prevent a race from making any advance towards civilization, as was to be seen in the condition of the inhabitants of the Arctic and Antarctic regions; while some lands, such as Spitzbergen and Nova Zembla, seem incapable of supporting human life at all. The absence of mountains and large rivers, and the obstacles presented by the great growth of forests, were exhibited in the characters of the effete Australians, and the tropical Andaman Islands exhibited a race of small abject savages, among the lowest in the world, while they were at no considerable distance, on the one hand, from the handsome and civilized Hindoos, and on the other, from the wellfed and well-clothed Burmese. In the Southern Hemisphere, New Zealand, with its fertile soil and high mountains, securing a perennial supply of water, presented inhabitants that, of all wild races with whom the Europeans had come into contact, showed themselves the most courageous and spirited, although they had sprung from the effeminate people of the intertropical isles of the Pacific, a difference of character which could hardly have arisen from any