Imatges de pÓgina

172) on the 5th of February." Since attention was directed to the group of asteroids by the discovery of Astræa in 1845, so many of these minor members of the solar system have been found that additional discoveries fail to excite much interest.

From the Observatory at Marseilles we have also the announcement of a new comet discovered by M. Borrelly on the 9th of February. It was soon afterwards independently detected by Herr Pechüle at Copenhagen. The comet presented the appearance of a round nebulous mass, with a small central nucleus, and an apparent diameter of ten minutes. It was nearest to the earth on the 18th of February, when its distance was about equal to that of the planet Venus when she is nearest to us. The spectrum of the comet was examined by Father Secchi, who found it to consist of three bands, so faint, however, that he was unable to fix their precise positions.

The recent appearance of a new German journal devoted to Crystallography and Mineralogy 12 is an event well worthy of note, not only for its own sake, but as significant of the position which these sciences hold in Germany, and which strikingly contrasts with their position in this country. To the English observer, accustomed to the scanty mineralogical literature of his mother-tongue, it might have seemed that there was already in Germany a sufficiently large serial literature occupied with mineralogy and the cognate sciences. Need we point to the Mineralogische Mittheilungen, so ably conducted by Professor Tschermak, of Vienna? Is not the famous Neues Jahrbuch of Professors Leonhard and Geinitz largely occupied with mineralogical papers? And do we not find mineralogical researches recorded in the Zeitschrift of the German Geological Society, in the Berichte of the German Chemical Society, in Poggendorff's Annalen, and elsewhere? Yet, with all these publishing media open, Professor Groth has felt that there is room for a new journal devoted mainly to crystallography, and subordinately to general mineralogy. And no doubt he is right. Aided by some of the ablest mineralogists in almost all parts of the world, he has brought out an opening number which gives promise of a very highclass journal. In turning over its pages, however, the reader becomes uncomfortably conscious of the inconvenience of not having a settled system of crystallographic notation. The formulæ are, in fact, written in most cases in the two rival systems-that is to say, in the notation of Professor W. H. Miller, and also in the more popular notation which Naumann introduced. It is clearly a waste of energy to have to express the same thing by two sets of symbols, written

11 Observations de la Comète découverte par M. Borrelly.' Comptes Rendus, No. 8, p. 336.

12 Zeitschrift für Krystallographie und Mineralogie. Unter Mitwirkung zahlreicher Fachgenossen des In- und Auslandes herausgegeben von P. Groth. Leipzig: W. Engelmann. No. 1, 1877.

side by side, just as chemical formulæ are often written doubly, according to both the new and the old systems.

In calling attention to Professor Groth's new journal we have but performed a pleasing duty; to attempt its analysis, however, would carry us into technical details unintelligible to most readers. Notwithstanding the vast mineral wealth of Britain, mineralogy treated scientifically has met with but little encouragement in this country; yet it is pleasing to observe that there are not wanting signs of an awakening to its real value. Indeed, within the last few months. two new societies have sprung into being-the Mineralogical and the Crystallological. Still there can be no question that to the English student the inorganic branches of natural history are far less fascinating than the biological branches. It is therefore to these sciences that we now pass.

Everyone interested in the subject of spontaneous generation will remember that Professor Tyndall made, last year, a series of ingenious experiments in which he adopted the method of subsidence for purifying the air to which his putrescible infusions were exposed-that is to say, he placed the infusion in chambers washed on the inside with glycerine, and, before commencing the experiment, allowed the air to settle until a beam from the electric lamp revealed no motes in it. By these means all putrefactive germs falling on the bottom and sides of the chamber were caught by the glycerine, and infusions of various sorts-animal and vegetabie-could be kept in the chamber for any length of time without showing the slightest tendency to putrefy. A similar set of experiments has recently been made by the Rev. W. H. Dallinger,13 who, operating with the germs of known organisms, has been able to show the rate at which these living motes fall through the air, and the time after the expiration of which, putrescible fluids, in a still atmosphere, are out of danger from their contact.


When a maceration fluid-such as an infusion of fish in wateris allowed to dry up, it forms a light, hard, porous, papier-mâchélike mass,' in which are contained, in incalculable millions, the germs of those organisms to which the putrefaction of the fluid was due. A cake of this sort was taken, derived from a fluid known to contain the germs of two forms of monad, the life-history of which Mr. Dallinger had worked out, namely, the 'calycine monad' and the 'springing monad.' A small quantity of the powder from this cake was dried at 150° F., a temperature 15° above that required to kill the adult form, and was then diffused through the air of a Tyndall's chamber. In this chamber were placed vessels containing a putrescible fluid, some open, some covered with lids which could, by a simple mechanical contrivance, be removed without disturbing anything else. 13 Monthly Microscopical Journal, December 1876.

Twenty-four hours after the exposure of the open basins to the mote-laden atmosphere, the covers of the others were removed, and everything was left for a certain time, after which first the open and subsequently the remaining basins were examined. It was then found that in those which had been exposed to the air from the first the calycine monad occurred in every drop taken from every vessel, and the springing monad in two-thirds of the drops examined. In the vessels which had not been exposed until the air had settled for twenty-four hours, the calycine form was wholly absent in three vessels out of four, and in the others occurred only in four drops out of thirty, while the springing form flourished in every vessel.


The reason of these facts is very curious and very interesting. The calycine monad is a giant of its kind, being about inch in length, while the springing monad is not longer than inch. The germs of these naturally bear some proportion to the size of their parents, and, consequently, the minute particles of protoplasm which constitute the spores of the calycine monad were some ten times as heavy as those of the other, and had nearly all fallen and impregnated the fluid in the open basins before the covered vessels were exposed. Mr. Dallinger put the matter to a further test. There is one monad, the uninflagellate' form, upon which many of his observations had been made; this in its adult state is about 4000 or 4 inch in length, and its spores are so small as actually to be invisible with the highest powers of the microscope. Dust from a dried cake containing these spores was mixed with some containing the comparatively gigantic calycine form, and the former experiment repeated. It was found that nearly all the 'calycine' germs had fallen in twenty-four hours, all in forty-two hours, for vessels exposed after the lapse of the last-named time contained not a single calycine monad, while every drop taken from them swarmed with the little uninflagellate form.



Mr. Dallinger has thus shown most conclusively that whenever a putrid infusion dries up there will be found a powdery mass containing spores which every breath of air will diffuse far and wide, and that some of these spores are so minute as to require two days to fall a few inches in a perfectly still atmosphere, so that the distance to which they could be carried, and to which they could spread contagion, is practically unlimited. The bearing of this on the germ theory is obvious enough.

Some months since, the spontaneous generation controversy arrived at an important crisis. Results of the most conflicting character had been obtained by different observers, and a settlement of the question seemed further off than ever. But, about the middle of last year, Dr. Bastian earned the gratitude of biologists by narrowing the point at issue, and giving, for a time at least, a definite

direction to future experiments. He announced, at the meeting of the Royal Society on the 15th of June, that he had discovered the precise conditions under which living organisms were infallibly produced in certain putrescible but sterilised organic fluids. If this supposed discovery were a real one, its importance could hardly be over-estimated; for if once the conditions requisite for development of life de novo in an organic fluid were ascertained, it would be but one step further to imitate those conditions in a manufactured fluid of known composition, and thus to gain some conception of the way in which the first germs of life may have originated on the earth. The theory of evolution would thus be complete at one end of the scale of being, and would receive a confirmation of its truth which 'none of our enemies would be able to gainsay or to resist.'

The needful conditions for the spontaneous development of life in boiled organic fluids are, according to Dr. Bastian, the neutrality or slight alkalinity of the fluid, or its maintenance at a tolerably high temperature (115°-120° F.). He placed his putrescible fluid (urine) in glass retorts, into the necks of which he introduced a small sealed glass tube drawn out to a fine point and containing enough potash solution to neutralise the fluid, the potash having been previously heated to the temperature of boiling water. After the introduction of the potash tube the retort and its contents were subjected for some minutes to the boiling temperature; the neck of the vessel was sealed during ebullition, and, after cooling, the potash was liberated by a shake sufficiently violent to break the capillary tube.


Under these circumstances Dr. Bastian found that in every case the fluid swarmed with bacteria after a longer or shorter time; while no organisms were developed if it remained acid, or if an excess of alkali had been added. Even under these latter circumstances, however, a copious development of bacteria was insured by keeping the fluid at a temperature of 122°.

This is Dr. Bastian's case. But it will be observed that he failed to mak sicker' in two important points: in the first place there was no proof that the fluids in question would not have developed bacteria without the addition of the potash; and, secondly, the potash was heated only to the temperature of boiling water, a temperature which, though amply sufficient to kill adult bacteria, has been proved, in many cases, to leave their germs unslain. It became essential, then, to repeat the experiments, allowing the fluids to stand sufficiently long, before adding potash, to make it tolerably certain that no organisms would be developed without the addition of the alkali, and to heat the potash to a temperature considerably above the boiling point of water, so as to insure the complete destruction of the most enduring microphyte-germs.

"Proceedings of the Royal Society, 1876, vol. xxv. No. 172.

Experiments with these necessary precautions have lately been made by Professor Tyndall and Dr. W. Roberts, of Manchester, and their results seem to demonstrate, conclusively enough, the fallacy of Dr. Bastian's conclusions.

Dr. Roberts's experiments 15 were conducted in the same manner as Dr. Bastian's, with one or two important modifications. In the first place the tube containing the proper quantity of potash for neutralisation of the fluid was heated, in an oil bath, to a temperature of 280° F., 68° above the boiling point of water; secondly, after the flask containing the boiled fluid with its contained potash tube had been hermetically sealed-of course during ebullition-it was allowed to stand in a warm place for a fortnight, and thus prove its complete sterility. The potash tube was then broken, and the flask exposed to a temperature of 115°, and afterwards to one of 122°; that is, the fluid was exposed to the very conditions which, according to Dr. Bastian, are most potent in inducing spontaneous generation. Nevertheless every one of the flasks was found to be absolutely sterile. It must be observed that not one of the essential conditions was alteredpotash is no more affected by the temperature of 280° than by that of 212°; the putrescible fluid was only boiled, under the ordinary atmospheric pressure, for five minutes, so that its composition could have been in no way altered, and yet the results obtained were, without exception, negative.

In Professor Tyndall's 16 experiments the same course was adopted, except for the fact that the potash was heated only to 220° F. instead of 280°. Again the results were negative. Professor Tyndall, as usual, brings forward a 'cloud of witnesses' to prove his position, and says: The experiments have already extended to one hundred and five instances, not one of which shows the least countenance to the doctrine of spontaneous generation.'

Similar results have been obtained in France by M. Pasteur, and once more there seemed to be some promise of a settlement of the difficulty, when Dr. Bastian communicated to the French Academy the results of further experiments in which he had heated his potash to a temperature above that prescribed by his opponents and for a longer time, and, under these circumstances, he always obtained a copious development of bacteria.

Thus, then, the matter now stands with regard to this particular experiment, and the question seems to have become one of experimental ability between the upholders of the two opposing views. There are, however, certain facts recently brought forward by Professor Tyndall, which throw a very important light upon the possible cause of such extraordinary discrepancies.

It is a well-known fact that dried peas resist the action of boiling

15 Proceedings of the Royal Society, vol. xxv, No. 176.

16 Loc. cit. p. 457.


VOL. I.--No. 3.

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