same period, and recommendations as to work dur- could only be done by placing a compound body ing the coming year.

above the simple lens. The President then ex

The Society then proceeded to the election of hibited the instrument which he had devised to officers, as follows:

President-Prof. H. A. Johnson.

meet these requirements, and pointed out that it consisted of a glass stage, having a large aperture

Vice-Presidents-H. H. Babcock and Lester Cur- in the centre, and mounted horizontally upon

tis.

three supports, one of which was formed by the pillar of the body; in this way it stood with great steadiness, and was strong enough to bear con

Treasurer-W. H. Summers. Recording Secretary-E. B. Stuart. Corresponding Secretary-Prof. William T. Bel- siderable pressure. The lens was carried by an field, M. D.

arm projecting from the pillar, and made to turn

Trustees-H. W. Fuller, Jas. Colgrove, Prof. E. aside horizontally when required; focussing and G. Bastin, B. W. Thomas, H. F. Atwood.

The Society then passed a vote of thanks to Mr. Fuller, for his long-continued and faithful efforts in its interests during his presidency (a period of eight years).

President Johnson and Messrs. Babcock, Curtis, Fuller and Stuart, were elected a standing committee on micrometry, with power to appoint a delegate to the National Committee. Adjourned to fourth Friday in May.

ERNST B. STUART, Secretary.

illumination were managed in the usual way, but there was a slow motion in addition to the rackwork. In offering the instrument for discussion, the question would arise as to the best form of lens to be employed, and he hoped to receive the opinions of the members upon this and other matters; but at present he used an ordinary lowpower achromatic objective made so as to slip into the arm without screwing; there was great convenience in thus mounting and using a simple lens. With the old doublet there was much difficulty in working comfortably, and whether a person could do so or not depended a good deal upon his nose, being specially troublesome in the case of those persons who had somewhat aspiring noses. In addition to the lens which he had placed upon the instrument, there was another belonging to it of half the focal length. Now, supposing they had made their dissection successfully, the point was how to be able to convert the instrument at once into a compound microscope without disturbing either the lens or the object. One of his aims in life had been to get microscope makers to abolish screws, which he regarded altogether as abominable inventions, and in this instance, the compound body had been made to slip over the outside of the socket in which the objective had been placed. This plan answered fairly well, but he thought it would be better to have it made to fit rather more easily, and to be secured by a bayonet joint, because, supposing that the power employed

Dissecting Microscopes.—At a meeting of the Quekett Microscopical Club, held Nov. 22, 1878, the following interesting discussion was held on this subject, Prof. Huxley, F. R. S., President, in the chair: The President said that the subject which he wished to bring before them that evening was a sort of contrivance which he had recently adopted himself, for the purpose of making dissections. They would all be aware that in a microscope to be used for delicate dissections, certain qualifications were absolutely essential. In the first place they must have perfect steadiness, the stand must be firmly and well supported, and be of sufficient strength and weight to bear the pressure put upon it without moving. Next it must be of convenient height, so that in working, the hands might get a steady support; it should fulfil these two conditions, and yet not be so large as to be clumsy. The next point was as to the lenses; they should be of such a form as to give a maximum of power, was not sufficient for the purpose, then inconveniand yet at the same time afford sufficient distance ence arose unless the body could be got off again between them and the object to admit of needles with sufficient ease to ensure the object remainbeing moved freely to an angle of 60° with the sur- ing undis.urbed by any jerk or movement. With face of the plate, because the efficiency of the the improvement of the bayonet joint, it would be needles obviously depended upon the angle at easy to remove the body, and having taken out which they could be used, and if a lens were made the first lens and dropped in, say a one-eighth with a wide face it would very often interfere with inch, the body would go on again without any the movements of the needles. Then there was disturbance. He had the instrument before them another point of still greater importance: When a made upon that pattern, to see how the thing careful dissection had been made it often became would work; he had used it for the past six or eight desirable to examine it with a much higher power months incessantly, and could certainly say that than the one which had served the purpose of for his requirements it was the best thing he had preparation, and provision ought to be made to seen, and he believed that with the little addition enable as high a power as was desired to be brought of a bayonet joint it would be as nearly perfect as to bear without disturbing the object, and this any instrument of the kind could well be. He

Wenham's illuminator inverted. He thought it would answer very well with a lens inserted into the wide end; he was, in fact on the point of having one made, to try.

thought that all persons who had been occupied him of adapting something like the "speculum in making minute dissections would see that it had uteri" to the purpose, which would resemble a value, and met all the requirements of the most delicate work. He hoped that the members would examine and criticize it, and make any suggestions that occurred to them for its further improvement, for it was becoming of very great importance to examine thin sections and minute portions of dissections without subjecting them to any such disturbance as to cause the slightest alteration, and it was equally important to be able to bring to bear upon them under such conditions the highest powers that might be needed.

Mr. Charles Stewart was sorry to say that be must differ somewhat from their President as to the value of the binocular microscope in dissecting, for he had found it of the greatest use in the case of transparent objects, since it enabled him to recognize the precise position of one object above or below another, with a facility which he thought

Dr. Matthews inquired if the President spoke of was of the greatest importance. He also wished. dissecting in water?

The President said that he referred to dissection in a very shallow trough, and by transmitted light. Dr. Matthews inquired if the President had ever employed a binocular eye-piece for dissecting purposes?

The President said he must confess that he was rather heretical as to binoculars in such cases. What was really wanted was to have the object well lighted and well defined, For all ordinary purposes there was nothing better than a good watchmaker's eye-glass, because it was so readily adjusted to the work, and, with a good orbicularis, to keep it in place, there was no trouble in using it. Dr. Mathews explained that he meant the ordinary binocular eye-piece, and not the binocular microscope. Some persons had a difficulty in holding an eye-glass properly, and to meet such cases there was another plan for using a single lens, namely mounting it upon an elastic wire, which could be moved to or from the object as required, by the pressure of the head.

to bring before them a little matter which he thought might be of interest, as it was in some degree connected with the subject which had engaged their attention. In making minute insect dissections, he had often found the want of a perfectly structureless background upon which to pin the object, and upon which it might be treated with spirit, and set aside to work upon at leisure." He had tried various things, but at length Mr. Field, of the Ozokerit Works, gave him a small quantity of black Ozokerit (or black wax as they called it), and this seemed to answer admirably, for it melted at a low temperature, remained soft! enough to stick a pin into, and was absolutely unacted upon by strong alcohol, or water, or by any mixture of them. When required for use it was only necessary to put a few knobs of it in a saucer, and when it was warmed it flattened out over the bottom with as smooth a surface as could be desired. There were two sorts of it, one being a little harder than the other-he had brought some specimens of each with him to the meeting, both in the lump and run out in small saucers; the rims of these little saucers being ground off flat, a glass cover could be laid over them, and the contents would be preserved from dust, and, in a great measure, from evaporation also. One very great occa-sain to come out of it; if gutta percha was used, advantage about this stuff was, that there was no the spirit extracted a kind of gummy product from it, a stain came out of it, and it very soon became brittle, whilst even the best cork contained numer ous small cells, which got out after a time, and seemed to have a peculiar proclivity for attaching themselves to the most delicate nerves and filsments. The new substance seemed to him to fill tions, as it cou'd be made to line a trough with a want, and it was equally useful for large dissecvery little trouble.

The President said that there was sometimes a little difficulty about holding the glass in the eye at first. When a person was beginning to do so, he was apt to indulge in a good deal of impatient ejaculation; because, when he got absorbed in his work, he forgot the eye-glass, and let it drop sionally into the middle of his dissection.

Mr. Ingpen thought that a large spot lens would be found of value, so as to get a black ground for the illumination of delicate transparent tissues in water, especially as it would not exhibit the disturbance of the surface of the water by the needles. The President said that he generally used a black screen for latter purpose. There was one other point upon which he should like to have the opinion of the club, and that was upon the best way of illuminating things whilst working by daylight. He could not get on very well with the condensing lens, and found it rather troublesome; reflected light seemed to be the best, and he had often wondered if a polished hollow cone would be a good sort of thing to use.

EXCHANGES.

ing) for condensing lens on stand, or standard size Wanted to exchange, good slides (French mountslides of vegetable preparations. C. R. Barnes, Madison, Ind.

Wanted, a No. 3 eye-piece, 2-inch objective, or polariscope, in exchange for various well-mounted objects. John Walker, 810 12th avenue, S. Minne

Dr. Matthews said that the idea had occurred to apolis, Minn.

Organisms in the Blood, and the Germ learned concerning the embryos of the

Theory.*

Filaria sanguinis hominis, first discovered by the author in 1872, in the blood of persons suffering from Chyluria.

It seems evident from the account here given that we have still almost

E have here in a everything to learn as to the source and small illustrated parental forms of these embryo nemwork an able atoids found in the blood of man. The critical resume hypothesis of Manson concerning the of some of the part played by mosquitos as intermedimost important ate hosts (within which some of the emfacts previously bryos swallowed may undergo developknown on the ment, and from the bodies of which parsubject, together ent forms, capable of infecting man, may with others not find their way into drinking water) hitherto pub- seems, from the careful observations lished, tending made by Lewis, to be rendered more not only to in- than doubtful. The relations of these crease our knowledge, but also to throw organisms to the morbid conditions with light upon the general question of the which they are associated are, indeed, relations of the microscopic organisms full of the most puzzling difficulties. It found in the blood to disease. is somewhat doubtful whether the maNearly two thirds of the work refers ture form of this helminth has yet been to the existence in the blood of vegetal discovered, notwithstanding the obserorganisms of the type of bacteria, bacil- vations of Dr. Bancroft in Australia, and lus, and their allies, while the remaining of Dr. Lewis himself (as referred to on third relates to the existence in this situ- pp. 85-89). The fact of the persistence ation of animal organisms. We have in of the envelope of the ovum as a diathis latter part a brief but interesting phanous sheath, surrounding each of the history of what is known concerning the young embryos found in the blood of existence of nematoid hematozoa in the man, would seem to the writer strongly lower animals, and also of what has been to suggest the probability that the em*The Microscopic Organisms found in the bryos in question have been liberated at Blood of Man and Animals, and their Relations once into some portion of the vascular to Disease. By Timothy Richards Lewis, M.B., system, rather than that they have enArmy Medical Department, Special Assistant tered it from without by penetrating its to the Sanitary Commissioner with the Government of India. (Calcutta, 1879.) walls. If such a process of struggling

through tissues were to take place, their Manson in China, and might therefore thin diaphanous envelopes would stand naturally enough be considered as the a good chance of being torn and left source of the multitudes of embryo behind. nematodes found in the blood of these Nematoid helminths have long been animals. But if true for China, it ought known to occur in the blood of many also to hold good for India; yet Dr. birds, and Dr. Lewis says: "I have ex- Lewis says: "It seems somewhat strange amined a considerable number of the that, notwithstanding the marked preordinary Indian crow (Corvus splendens), valence of embryo hæmatozoa, the Fi and have found that the blood of nearly laria immitis has not, so far as I can half of those which have come under learn, been recognized in India. I have my notice have contained embryo hæm- often searched specially for it but in vain. atozoa of this character. Sometimes The only mature parasite which appears they are in such numbers as to make it to affect the circulatory system of dogs a matter of surprise how it is possible in this country is the Filaria sanguinothat any animal can survive with so lenta, a description of which, together many thousands of such active organisms with an account of the pathological distributed throughout every tissue of changes which are caused by it during its body. The birds did not appear to be its development in the walls of the aorta affected in the slightest degree by their and adjacent tissues, was published by presence. In their movements they are very similar to the nematoid embryos found in man; they are, however, considerably smaller, and manifest no trace of an enveloping sheath."

me in 1874.”* But then, the same writer adds: "Notwithstanding the circumstance that this is the only mature helminth which I have found associated with the embryo hæmatozoa of India, I cannot believe that there is a genetic connection between them, for it frequently happens that the mature worm may be present in abundance unassociated with blood embryos of any kind, and sometimes it is sound that the latter exist without any trace of the former."

Again, observations made many years ago by MM. Gruby and Delafond went to show that 4 to 5 per cent of the dogs in France harbored microscopic nematodes in their blood; Lewis ascertained in 1874 that more than a third of the pariah dogs of India are similarly affected, whilst Dr. P. Manson has shown What has been said above suffices to that this kind of parasitism affects at show the very considerable gaps in our least an equal proportion of dogs in knowledge concerning the life history of China. The embryo nematodes belong- the nematoid hæmatozoa of man and ing to dogs of these different countries animals, and also the tendency so freseem to agree with one another in all quently met with among some observers their characters. It is important to note to bridge these gaps by unsatisfactory that their presence is not associated with explanations deduced from a too-narrow the existence of any definite disease. survey of the facts a perennial source The dogs harboring such parasites are of error peculiarly common in regard to outwardly indistinguishable from others this class of questions. which have them not. Strange as this Of the protozoa referred to as being may seem, it is also strange that the found in the blood of the lower animals, mode in which the embryo organisms the newest and perhaps the most intergain access to the blood is still involved esting are those now first described by in great obscurity. It is true that, by the author as existing in that of rats. several observers at different times, Being directed by the Indian Governthread-like mature nematodes (Filaria ment to make observations on the spirimmitis) have been found in more or less abundance in the right chambers of the heart of the dog. These have been found to be extremely common by Dr.

illum occurring in the blood of patients suffering from the Bombay fever, the

*The Pathological significance of Nematode

Hæmatozoa.

author says: "Whilst doing this I had well known, and has been pointed out occasion to examine the blood of a con- by Virchow amongst others, that the siderable number of animals, and even- proportion of bacilli in the blood at tually (July, 1877) detected organisms autopsies bears no sort of relation to the in the blood of a rat which, at first sight, severity of the disease previously existing I took to be of the nature of vibrions or in the persons under examination spirilla." The organisms, of which fig- But it is in regard to these vegetal ures and photographs are given, are each organisms existing in the blood of man of them provided with a long and very and some animals that the larger part of distinct flagellum, though otherwise they Dr Lewis's memoir refers. He evidently are not very different in appearance from entertains a clear view of the principal some bacilli. Subsequent observations phenomena to be considered in reference showed Dr. Lewis that whilst such or to this part of the subject, and exhibits a ganisms do not seem to exist in the blood rare absence of a tendency, which is of mice, they are to be found in two unfortunately but too common, to slur species of rats, viz., Mus decumanus and over fundamental difficulties standing in Mus rufescens. Concerning their pre- the way of the acceptance of the "Germ valence and pathological significance in Theory of Disease" or the "Doctrine these animals, he says:-"I have examin- of Contagium Vivum," as it is sometimes ed the blood of a great number of rats termed. In addition to acute criticism, for the purpose of ascertaining what pro- Dr Lewis has made known some very portion of them contains these organisms significant and important new facts. in their blood, and find that of those! After referring to the generally received specially examined for this purpose, their view that organisms of the bacterium or existence was demonstrated in 29 per bacillus type do not exist to any recognizcent. Sometimes, however, the numbers able extent in the blood of healthy detected were very few, not more than animals, and to the experiments made one or two in a slide, but in the greater some years ago by Dr. Douglas Cunningnumber of cases they were very numerous, ham and himself, which showed how every slide containing several hundreds. quickly, after such organisms had been

With regard to the health of the rats purposely introduced into the blood of in which these flagellated organisms were healthy animals, they disappeared theredetected, there was nothing to suggest from, he says:-"It may be safely affirmin any way that they were less healthy ed that their presence in appreciable than others not so affected, and I have numbers is, judging from experience, repeatedly kept rats for a considerable incompatible with a state of perfect time for the purpose of observing whether health." The case in regard to these any special symptoms would be manifest-microphytes is, therefore, different from ed. When it is considered that what has been stated to obtain with the thousands of active beings of this animal organisms before mentioned, character can exist in the blood without which may swarm in the blood of in any appreciable manner affecting the creatures who are in other respects quite health of their host; and when it is healthy.

further considered that these organisms One or other of such microphytes has must consume at least as much, if not been found to be generally present in far more, oxygen than bacteria, bacilli, charbon or splenic fever, and in recurrent and spirilla, it becomes difficult to under-fever. M. Pasteur has of late maintained stand how it comes about that, to a like that septicemia is also characterized by action on the part of the latter is ascribed the existence of such organisms in the the asphyxia and the other morbid con-blood during life; and to this list Dr. ditions which characterize death from Klein adds the so-called typhoid fever of splenic disease and allied affections." the pig.

Such a view has been put forward by It is impossible to follow the author MM. Pasteur and Joubert, though it is through his discussion (pp. 11-34) of the