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group of facts than by actual observation. Mr. Crace Calvert, in a paper read in May before the Royal Society, alludes to the great difficulties of such investigations, and he specially signalises those arising from the rapid development of minute life under certain conditions. White of egg, for example, mixed with water free from life, and exposed for a quarter of an hour to the air in August or September, exhibited life in abundance. Even a momentary exposure to the atmosphere seems sufficient, as long since pointed out by Pasteur; but no one has hitherto been able to detect in the atmosphere that abundance of divers germs which the followers of Pouchet consider must exist therein if the panspermist theory is true. Few would now deny that living forms and their germs may exist in a condition so small, or so transparent, as to elude our best instruments; and it becomes practically impossible to start with establishing the negative proposition, that no life or germ exists in the materials or the vessels experimented with. One of the most interesting of Mr. Crace Calvert's researches related to the amount of heat minute germs of life will bear. He allowed life to be developed in sugar solutions contained in small stout tubes, and then gradually brought them in an oil bath to various temperatures. At 212° most of the living objects had disappeared, but some small black vibrions and three common ones still moved energetically. At 300°, sustained for half an hour, two ordinary and one or two black vibrions still moved; but at 400° and 500° no life was visible. The tubes were examined twenty-four days after the heating.
Much mental confusion exists on these matters from a vague use of the terms “life” and “living.” If we consider the complicated phenomena exhibited by creatures enjoying the higher forms of life, and if calling them “alive” is a short way of summing up their properties and actions, and if the same word “ alive" is used to sum up the smaller range of properties and actions of the most rudimentary objects of which life of any sort can be predicated, it is obvious that no precise meaning is attached to the term. Notwithstanding Dr. Lionel Beale's experiments, we have no reason for assuming that there is an abrupt and sharp transition from non-living to living matter, or that life consists in the action of a “principle” upon inorganic substances. We do not know what life is, and the less pretension of knowledge that does not exist the better the prospects of science will become.
Various questions of development are intimately connected with that of the origin of life, and many of them are much easier to study; and the more they are worked out the nearer we may approximate to some logical generalization that may conduct us beyond the regions open to direct research.
Mr. Metcalfe Johnson has communicated several papers on these subjects to the “Monthly Microscopical Journal.” Referring to that publication for details, and strongly advising that other microscopists should endeavour to repeat and test Mr. Johnson's observations, it may now be sufficient to state that he gives a series of drawings, showing what he believes to be intermediate forms between organisms hitherto supposed to be quite distinct. Thus he pictures certain amcboid forms changing gradually into a paramecium, and he traces the development of the philodine rotifers from elementary forms. “ Actinophrys sol,” he says, “is only a phase in the life history of Ameba.” The philodines he regards “ as stages of development of one common form of animalcular existence.” In another paper the same writer speaks of various forms of monads as being transitions to such creatures as Kolpoda Cucullus. It is of great importance that such statements should be experimentally investigated by other microscopists.
Among the recorded discoveries of new species during the past year is that of a very curious rotifer described by Dr. Hudson to the Royal Microscopical Society in September, and figured in the Journal. He names it Pedalion myra. It is remarkable for a prominent limb acting as an oar—whence its name—and in general appearance it suggests the idea of resemblance to the water-fleas. Dr. Hudson will, it is hoped, be able to furnish more details another season concerning its internal structure. At present he is satisfied that it is a rotifer with “six legs,” and its crustacean appearance suggests that if sufficient specimens are found for complete examination, it may strengthen the views of those who have thought rotifers nearer the crustacean than the annelidan group.
Professor James Clarke, of Pennsylvania, described in 1861 some very interesting infusoria roughly resembling in form vorticellids, surmounted by a delicate transparent glassy funnel, and furnished with a flagellum or whip filament; and Mr. W. Saville Kent has been so fortunate as to find them in a pond at Stoke Newington. The new forms are named Cadosiga, Salpingæca, Ricoseca, and Anthophysa. They were succinctly described by Mr. Kent to the Royal Microscopical Society in November, and will be found in the reports of their Transactions.* Careful illumination and good objectives seem necessary to see the “ hyaline collar” or funnel and the slender whip distinctly. When warmer weather arrives, ponds in various localities should be diligently searched for these interesting and beautiful objects.
Some papers concerning fungi which have been written
• “Monthly Microscopical Journal,” Dec. 1871.
during the year require notice. Mr. Jabez Hogg took up the question of the diseases said to be caused by a fungoid growth in India, and well known as the “ Fungus Foot.” The conclusion he arrived at was that the fungus was not the cause of the disease, but a growth taking place in dead matter suitable for its development.
In France considerable annoyance and alarm, as well as interest, was excited in the summer by the appearance of a yellow fungus, which has been named Oidium aurantiacum, in the “ munition. bread” furnished to the French soldiers in Paris. This fungus produces orange-coloured spots on bread, and was first recognised by M. Payen on its appearance in bread supplied to French soldiers some thirty years ago (1843). A small portion of bread afflicted with it is sufficient to inoculate any quantity. The precise cause of its appearance at uncertain intervals is unknown, and forms one of the subjects to be investigated by a commission to whom the whole question has been referred. M. Decaisne stated to the French Academy that he met with bread affected by this oidium (if such it is to be called) in Italy in 1862, at a place named Radicofani, and the landlord of the inn told him that it was the second time it had appeared in ten years. The first time, he said, it had not disagreed with anybody who eat it, but on this occasion he considered it had made one of his servants ill, and M. Decaisne found him suffering from vertigo, which an emetic removed.
M. Gauthier de Claubry stated that he had found bread similarly affected in 1831, at Chartres, with a fungus he considered uredo rubigo; and in 1842 he saw the same vegetation on the munition bread of Paris. He also discovered spores of this fungus in the wheat employed. It is not stated that this fungus -whatever its name ought to be-produced ill effects on the Paris troops last summer, but M. Decaisne says its action is uncertain, and that all loaves that may be attacked should be treated as unfit for food.
This bread fungus is the more interesting from having been one of the first, if not the first, of its tribe that drew the attention of observers to the curious and unexpected fact that its spores were not deprived of their germinating power by a heat equal to that of boiling water, to which the loaves must have been exposed in baking. Should any reader meet with this fungus, he should carefully watch its growth, notice its fructification, and sow spores on rice paste and other substances. It is probably not a true species, but a variety of some commoner kind.
Amongst miscellaneous matters which cannot now be more than alluded to, it may be remarked that Mr. H. J. Carter bas adduced reasons for considering cocoliths as plants allied
TOL. XI.-NO. XLII.
to Melobesia calcarea. The same observer has likewise contributed to the knowledge of sponges by an interesting experiment. He fed a marine calcareous sponge with indigo, examined it at the moment, and then preserved it in spirit, where he says 66 it now shows all the cells (monociliated) with the cilium attached, and the indigo still in the cells.”
From Professor Norris, of Queen's College, Birmingham, we learn that not only do blood corpuscles pass through the walls of blood vessels, as previous observers had seen, but that some explanation may be offered of the puzzling fact of their doing so without the previous existence of apertures, or any trace thereof after they have passed through. He arrives at the following generalization: That a rigid or plastic body can pass through a colloid film, if there is, first, an intimate power of cohesion ; secondly, a certain amount of pressure from within ; thirdly, power of the substance of the film to cohere to the surface of the body, or to some intermediate matter which already coheres to the surface during its passage; and fourthly, cohesive plasticity of the particles of the material of which the film itself is composed, so that the breach in it may again become united as it descends upon the opposite surface of the body which is being extended. This is a view of the matter that requires to be supported by experiments with colloid films.
The mode in which silica is deposited in various plants, and especially in diatoms and others, which exhibit that mineral in regular patterns, has engaged the writer's attention, and he regards it as probable that the deposit usually takes place, not from the decomposition of an alkaline silicate, as usually supposed, but from a solution of pure silica in the colloid state, dissolved by rain-water. Such a deposit taking place slowly, through a plant membrane or on its surface, might be expected to assume the form of minute spheres, separated or coalescing according to the rapidity of the process, the quantity of silica in solution, and the exact nature of the surroundings. Quick deposits from rich solutions would probably lead to coalescence in amorphous forms, as seen to a remarkable extent in the bark of the curious pottery-tree, where it is found in lumps. If these views are correct, it is probable that all diatoms. bave their siliceous skeletons composed of spherules; and a careful examination not only of the so-called “ costæ,” but also of some of the apparently plane and homogeneous surfaces of pinnulariæ, lead to the conclusion that such is their structure. The so-called “costa” are not solid ribs at all, but curious and complicated beaded structures. These views were brought before the Royal Microscopical Society in a paper published in the August number of the Journal.
The writer also called attention to the modifications of crys
talline forms produced by dissolving the substance to be crystallized in an aqueous solution of colloid silica, instead of in plain water. Figures of the patterns obtained will be found in the Journal for March 1871. Objects so prepared are of unusual beauty when seen with the polariscope.
The attention of microscopists should be called to a series of papers by Dr. Braithwaite on the structure of bog mosses, which belong to the Transactions of the Royal Microscopical Society. They will be found to suggest very interesting observations concerning the minute structure of these highly curious and exquisitely formed objects, as well as indications of their true place in classification, which is higher than was formerly supposed.
Many subjects belonging to minute anatomy and physiology that have been investigated during the year, especially in Germany, are too technical for popular interest, but in addition to what has been already mentioned, Dr. Lionel Beale's discovery and beautiful exhibition of the nerves accompanying capillary vessels well merits notice. Whatever may be thought of portions of Dr. Beale's reasoning, and of his antagonism to views of evolution or development, he stands in the very highest rank, if not at the very summit of observers. His skill in preparation is quite remarkable, and his employment of the highest and finest powers places him in advance of all competitors less painstaking or provided with inferior optical means. Most physiologists will, it is apprehended, infer from the existence of capillary nerves, that they play an important part in controlling the circulation through minute vessels.
M. Georges Pouchet has arrived at the conclusion that the sudden change of colour observable in certain fishes arises from the action of nerves upon their chromoblasts, or colour cells.
In approaching the conclusion of these remarks, which have no pretensions to be exhaustive, the use made of the microscope by Mr. W. Kitchen Parker in his extremely valuable and remarkable morphological researches ought not to be omitted. Morphology is quite a modern science, and throws strong light upon such questions as the origin of species, Darwinian theories, &c. &c. Its object is to trace the earliest appearance and formation of special parts and organs in various animals, and to compare parts which are similar in origin and position in all the creatures in which they can be discerned, and in all stages of growth. Mr. Parker's attention has been recently given to the development of the skull in tadpoles and frogs; and although an intimate acquaintance with comparative anatomy is necessary to follow various details, the broad results are as simple as they are instructive. He finds, for example, in the tadpole skull indications of higher types, and even of