urine of a healthy man is free from germs, but in the majority of cases it meets with different kinds of germs at the orifice of the urethra, or in the air in the neighbourhood, during its emission. He also described the very simple apparatus which he had employed in repeating Dr. Bastian's experiments, in which he was aided by MM. Joubert and Chamberland.

An American Infusorial Stratum.—In a late number of the Proceedings of the Boston Society of Natural History,' Mr. Charles Stodder states that Mr. R. B. Tolles examined the stratum as it is exposed in a ravine on the west side of Shockoe Hill, near Richmond, and obtained specimens at the depths, 5, 71⁄2, 10, 11, and 14 feet below the top of the bank, and also from the north side 40 feet below the top, from a bed which was apparently a continuation of the 14-feet bed, the hill being higher on the north side. The lower layer contains 50 to 80 per cent. of organic forms, the uppermost about 20 per cent. The species below this top layer vary but little; while in that they are partly different in species, and the frustules are less broken. The species of diatoms peculiar to it are: Coscinodiscus perforatus, Aulacodiscus crux, Eupodiscus Rogersii, and Mastagonia actinoptychus. Mr. Stodder gives a list of the species afforded by the several beds.

6

Dr. Tyndall and Dr. Bastian before the French Academy.-The Comptes Rendus' of July 31 contains the following extract, which is made from two letters sent by Dr. Tyndall to M. Dumas : "M. Tyndall writes to M. Dumas on the 26th of July from Brigne, in the canton of Valais, that he has been surprised to learn from the 'Compte Rendu' of the 10th of July that Dr. Bastian points him out as bearing evidence to the exactitude of his experiments. He says that he finds, on the contrary, that at a temperature of 50° Centigrade, furnished by the Alpine sun, nothing supports Dr. Bastian's ideas. All that Dr. Bastian alleges in favour of spontaneous generation fails to manifest itself. In a second letter, dated July 29, M. Tyndall, after having read M. Pasteur's reply to Dr. Bastian, gives his entire adherence to our colleague [M. Pasteur], and calls on all enlightened persons to banish from science this doctrine of spontaneous generation, which has nothing whatever to support it."

The Characters of the Blood in Anomia. This has been carefully gone into by M. G. Hayem-whose blood-measurer, our readers will remember, we exhibited at the soirée of the Royal Microscopical Society --who draws the following conclusions from his paper before the French Academy of July 17. We may mention that he arrives at a result quite different from that of Dr. Wharton Jones-viz., that there is no relationship whatever between the red and white corpuscles of the blood. The conclusions are:-(1) The red globules are very alterable elements; (2) It results from their alterations, in chronic anæmia, that their feebleness of colour or of their power of colouring the blood and the defect of concordance between this colouring power and the number of coloured elements, are the only two essential characters of anæmia; (3) That if in the anæmia the total mass of

blood remains the same as in the normal state, which appears to be the case in the majority of instances, the determination of the colouring power alone gives an exact measure of the degree of anæmia; (4) It is useful to distinguish in pathologic physiology the modifications which are related to the generation of globules, from those which belong to the evolution of these elements.

He concludes his paper by saying that in anæmias of median intensity the formation of red globules, so far from being relaxed, is often more active than in the normal state. But they are attacked in the course of their evolution, which thus becomes incomplete. The case must be severe indeed where one sees a relaxation in the formation of red globules.

NOTES AND MEMORANDA.

A Microscope Stage and Lamp.-Mr. J. E. Smith, of Ashtabula, Ohio, U.S.A., writes to the Cincinnati Medical News' as follows:— Some nine years since, I purchased one of Zentmayer's "Army Hospital Stands." It has been in constant use to the present time. A few weeks ago I begged Mr. Zentmayer to make me a new revolving stage, one thin enough to admit oblique pencils up to 80° from axis. Mr. Zentmayer kindly responded to my request, and I now enjoy a very complete stand, serviceable for all work. To the many who own Army Hospital Stands, I would say, do not abandon them, but " go and do likewise;" and for the benefit of such I append a brief description of the new stage. It is 4 inches in diameter, and a little less than of an inch in thickness at the periphery, decreasing towards the centre to about of an inch at the well hole: the reasons for this are obvious. The stage consists of two plates, the lower one being securely attached to the "limb of the stand, and is furnished with adjusting screws for centering; over this the upper plate is fitted concentrically, and revolves in the optical axis of the instrument; this plate in turn supports the object carrier which traverses the revolving plate with easy and smooth friction, regulated by a binding screw; the carrier is also furnished with a removable stop, for use with the Maltwood finder. Another plate, about 3 inches in diameter, fitted with tube for carrying sub-stage appliances, connects by a bayonet catch to the under surface of stage, and has a sliding movement for centering purposes; this plate can be placed in position or removed therefrom instantly. Notwithstanding the extreme thinness of this stage, I find it to be sufficiently firm. Those, however, who expect the solidity found in English stages, 12 inch thick, will be disappointed.

دو

I have lately modified my German student's lamp, and get illumination superior to the round Argand burner. The change is easily made with any model of student's lamp, having removable burner, and the cost will not exceed fifty or seventy-five cents. A friend called

my attention three or four weeks ago to a novel arrangement of a bull's-eye condensing lens, in connection with lamp and mirror. At first sight I was pleased with this method of illumination, and have given the idea considerable study, resulting in a slight change of the arrangement suggested for oblique light work, especially the resolution of difficult diatoms, such as Nos. 18, 19, and 20, of Möller's (balsam) Probe-Platte. The method will be found very superior, easily manipulated, and inexpensive.

Cement for Glycerine Mounting.-Mr. Kitton, whose authority on this subject is admitted, gives the following piece of advice in a recent number of 'Science Gossip':-White lead in powder, red ditto in ditto, litharge in ditto,-equal parts of each. These are ground together with a little turpentine until thoroughly incorporated, then mix with gold size. The mixture should be sufficiently thin to work with the brush; it is perhaps scarcely necessary to say that the edge of cover and slide should be free from moisture before applying the cement, and the first coat allowed to dry before putting on a second. The last can be applied somewhat thickly, or, as the japanners say, floated on. No more of the cement should be made than is required for present use, as it soon sets and becomes unworkable. To save the trouble of grinding, a stock of the mixture can be kept ready ground in a bottle.

M. Cornil's Experiments on Staining Materials. In a memoir devoted to the subject of amyloid degeneration of the kidney, liver, and spleen, which appears in a recent part of the Archives de Physiologie,' M. Cornil gives the results of his experiments with several new colouring matters. Two of these were methyl-aniline violets discovered by M. Lauth; the third was a violet discovered by Dr. Hofmann, of Berlin. The preparations can be stained with these violets either when fresh or after being hardened in spirit; and the colouring agents have this peculiarity, that certain tissues, as cartilage, decomposes them into a violet-red and a blue-violet, each of which becomes fixed in different elements of the tissue; the hyaline matrix, for example, assuming a red colour, whilst the nuclei and cellules, as well as the cartilaginous capsules, become of a blue-violet tint. The normal tissues of the liver, kidney, and spleen, however, do not decompose the violets, but, when amyloid degeneration is present, the degenerated and semi-transparent parts resembling colloid become of a violet-red, whilst the normal elements are tinted of a violet-blue, and thus a means equal, if not superior, to that of iodine is afforded, by which the changes may be followed.

A Double Weight for Balsam Mounting is described in the 'American Journal of Microscopy' (No. 4), by the Rev. J. L. Zabriskie. He says, in mounting microscopic objects in balsam by the use of the hot-water bath, and a weight upon the covering glass -which process is slow, but sure-one usual difficulty to be overcome is the tendency of the cover to gradually slide away from its original central position. I do not know if this plan has been adopted before;

but I have found the little home-made apparatus here described very satisfactory in conquering this difficulty.

Two bullets are slightly flattened at one point by a few light blows with a hammer, so that they will stand on this flattened part without any tendency to roll. A piece of No. 16 iron wire, half an inch long, and sharpened at one end, is driven into the opposite part of each bullet for a handle. A gash, inch deep, is also cut in the side of each, which may be readily done with a hammer and a stout-bladed pocket-knife. A strip of tin-plate, inch wide and 2 inches long, is cut, and each end of the strip is thrust in the gash in a bullet, where the tin can be firmly secured by hammering the gash together with the sharp edge of a tack-hammer, or other suitable tool. A cube of cork is cemented at the middle of the under side of the tin strip, of such thickness that it will touch the covering glass when in use, and a varied pressure can be obtained from the weight of the bullets by slightly bending the tin strips up or down, before the apparatus is placed in position. Care should be taken that each bullet just touches the glass, in which case the slight springing of the tin strips will act as a lever, with the cork as a fulcrum; and if more pressure is needed, it can be had by placing an additional weight on the cork.

The advantages of this method are, that nothing projects beyond the edges of the glass slip, to take up unnecessary room or receive any accidental disturbing blow; and if the double weight is applied while the slide is cool, and the balsam slightly stiffened, even if the top of the hot-water bath is not perfectly level, the covering glass will be securely kept for any desired time, without the slightest change from its original position.

The best Mode of examining the Umbilical Cord of Mammalia. Mr. Lawson Tait, who has recently read a very valuable paper on the structure of the cord before the Royal Society,* gives the following as the best mode of preparing specimens. He says:-First of all I may say that I have in no instance drawn a conclusion from observations made on a cord otherwise than perfectly fresh, unless it is distinctly stated to the contrary. I have found the examination and treatment of tissue which has been subjected to hardening reagents so unsatisfactory that I have quite discarded it.

All my sections are made by the freezing process (described in Humphrey and Turner's Journal for May, 1875), so that sections of the perfectly fresh cord of about of an inch in thickness have been examined. These have been subjected to various treatments —as simple clearing by glycerine, destruction by acetic acid, staining by silver lactate, and by my various indifferent staining fluids, hæmatoxylin, litmus, cabbage, &c. (also described in Humphrey and Turner's Journal).

My injecting apparatus is so arranged that it acts automatically when set at work. The tissue injected and the whole apparatus is surrounded by a current of warm water, the temperature of which is registered. The injecting force is supplied by compressed air ad

* Proceedings of the Royal Society,' No. 168.

mitted directly to the surface of the injecting fluid, and the pressure is registered by a manometer. The nozzles used vary in diameter from 1 to 4 millims. The fluid used is a 10 per cent. mixture of Seitels's Berlin blue suspended in firm size. This does not stain the tissue, because it is not in solution, yet its granules are too small to be seen by any power of lens in my possession. That it is not in solution is certain from the fact that it is completely removed from the fluid by adding some albumen and boiling. Similar but not so satisfactory results may be obtained by Davies's granular carmine; but here the granules are too large to enter the canals, save under such pressure as produces frequent extravasation.

One disadvantage of the Berlin blue is that it contains a little free acid, and must do so to remain visible. After a short time this acid destroys the colouring of the stained nuclei; so that, save in an almost perfectly fresh specimen, it is impossible to demonstrate the relations of the nuclei to the canals when distended by the injection.

The method of injection of these canals is apparently very rough. It consists simply in inserting a small nozzle superficially into the substance of the cord over and parallel with the course of a vessel, tying it in, and injecting under a low pressure of 50 or 60 millims. of mercury.

Schweiger-Seidel made the very obvious objection to this (Recklinghausen's) method that any appearances presented by it would be simply those of extravasation. Such was my own belief when I first tried it on the cord; but very short experience showed me that the result was a regular and uniform injection of a system of canals, and that extravasation was very rare and always limited to the immediate neighbourhood of the wound in the cord. With the whole apparatus at a temperature of 47° and a pressure of 60 millims., I have injected a column of the cord for a distance of 9 inches in about half an hour. The injection travels rather more rapidly in the direction from the child to the placenta than in the opposite direction.

I have repeatedly seen minute streams of the blue injecting fluid flowing from the surface of the cord into the water surrounding it, even at as low a pressure as 55 millims., with a nozzle only 1 millim. in diameter; yet at a pressure of 350 millims. I have not produced a rent in the surface of the cord, though I have produced numerous extravasations into the alveoli and into the neighbouring columns.

American Observations on Cellulose in Blood.-We desire to call attention to the published results of Mr. T. Taylor's (Government Microscopist, U.S.A.) investigations, which we think are likely to bring American science into contempt. He has lately been publishing a series of papers, which are the veriest nonsense in reality, so much so that we are surprised at their appearing as they do in a Government report. In the first place, the author never takes the trouble to inquire what has been done in European countries on the subject, and he plunges into a complex question entirely foreign to his pursuits, and the highest power he has employed is 150 diameters. Why, he could barely see the blood-globules of man with such a power. Will anyone who has ever examined the blood under a high