The very curious Parasitic Crustacean, the structure and larval form of which we propose to consider in the following communication, we obtained in the month of August last, in considerable numbers, in the branchial pouches of a Lophius piscatorius, which we captured at Whitby in Yorkshire.

The first example of this, apparently little known, species of Parasitic Crustacean appears to have been noted by Professor Otto. The celebrated Swedish naturalist Retzius was, however, the first to give, in 1829, an anatomical description of it. He named it Lernœa Dalmanni. His description was accompanied by several figures, which, though in many respects imperfect, enable one to recognise the chief external characters of the animal. He found three specimens at Christian Sound, in the nasal cavity of Raia Batis. Von Nordmann obtained from Rudolphi the specimen discovered by Otto, but it was so injured, that he adopted, in his account of the anatomy of the animal, the description of Retzius. Some years afterwards, in 1836, Kröyer added it to the Danish fauna. He states that he obtained two specimens from the nasal chamber of a skate brought to him by a fisherman from Aal-back, and that specimens from Iceland had been for several years in the possession of the Natural History Society. As naturalists had now begun to subdivide the old Linnean genus Lernæa into various genera, Kröyer added this animal to the genus Lerneopoda of De Blainville, and, continuing its specific name, termed it Lerneopoda Dalmanni.

In compliance with the desire which the Council have done me the honour to express, I have drawn up the following account of the recent progress and present state of Sanskrit studies, prefixing such an outline of the earlier history of these researches as may serve to complete the review, and render it more easily intelligible.

In this sketch I do not profess to communicate anything new, but merely seek to present such a summary of the results already obtained, as may convey to those who have not bestowed any special attention on the subject some idea of the character and affinities of the Sanskrit language, and of the nature and contents of Indian literature, as well as of the advances which have of late years been made in the principal branches of the study.

In pursuance of an idea which occurred independently to Professor Tait and myself, a careful examination has been made of the solar autographs, taken at Kew and Cranford, under the superintendence of Mr Warren De la Rue. This was done with the view of detecting, if possible, some reference to planetary configurations in the behaviour of sun-spots, and in this undertaking, much aid was derived from a remark once made by Mr Beckley of Kew, when taking pictures of the sun, to the effect that, for a considerable period of time, he did not observe any spots in the act of breaking out on the visible disc of our luminary. A few words may not be amiss regarding the nature of the scrutiny to which the solar pictures were subjected, and also the value of this as a test of planetary action. In the first place, let us bear in mind, that by the rotation of our luminary, the different portions of his surface are successively presented to each planet in turn. Now, if the bodies of our system have any appreciable influence of this kind upon the sun, it is natural to expect that this should differ for any given portion of his surface, according as this portion is presented to the influencing body, or withdrawn by rotation, so that the sun's diameter is interposed between it and the planet. We should therefore expect to find that, for a given date, the spots should all begin to break out into visibility at or about the same ecliptical longitude. Similarly with regard to their healing up; and, generally, all spots on the sun's disc at a given date should behave in the same manner as they pass a given ecliptical longitude.

In the Transactions of the Royal Society for 1778, Mr Hunter has given an account of some experiments which he made on the freezing of the egg of the common fowl, from the results of which he inferred,—“That the fresh egg has the power of resisting heat, cold, and putrefaction, in a degree equal to many of the more imperfect animals, …. and that it is more than probable, this power arises from the same principle (a living principle) in both.”

As the means for making observations on the heavenly bodies become more and more exact, astronomers are compelled to introduce new refinements into their calculations; new inequalities are discovered, and the computation of those whose sources are already known has to be carried to a greater number of approximative steps.

Discussions on the amount of solar parallax, of aberration and of nutation, are now carried on to the third and fourth decimal fraction of a second; with such a refinement of computation, it seems almost impossible to proceed too far in the refinement of theoretical deductions, and on that account, it may not be inopportune to discuss the influence which the sun's and moon's attraction exert upon the direction of the plumb-line.

Before proceeding to the subject of this paper, I wish to advert to the following well-known theorem.

Let ABC be any triangle with its inscribed and circumscribed circles. Then if we take any other point D in the exterior circle, and draw the tangents DE, EF, FD, the last tangent will come again to the original point D. A similar theorem is true of a polygon of any number of sides which is both inscribed in, and circumscribed to, a circle. Also if ellipses are substituted for circles. Of these theorems I remember to have seen a demonstration founded on the theory of elliptic integrals. But this appears to me to be a great waste of analytic power; for the theorem really results from first principles, as I think will be manifest from the following considerations.

Few departments of zoology have recently suffered more remarkable changes, both in classification and accepted views of structure, than the Polypi or Cœlenterata, and their immediate allies in the ascending scale, the Molluseoida,—greatly depending upon the more extended study of those animals of late years. We have been thus enabled to discover natural affinities which prima facie evidence would scarcely ever have indicated, as well as intrinsic differences which the same kind of evidence has hitherto been incapable of revealing to the mind.

Leading from the Protozoa to the Mollusca proper, the Cœlenterata and Molluscoida constitute an unbroken series of animals forming a considerable section of invertebrata, distinguished from the Protozoa by the development of true ova, and from the Mollusca by the property of gemmation developing compound examples of the principal types. Furthermore, the motion of the blood, or its equivalent, is effected either by ciliary action or by a propulsive organ; but when the latter occurs it is unfurnished with valves, so that the course of the circulation may be reversible in the same canals.

In searching for crystals of titanium between films of mica, I was surprised to observe something resembling the remains of insects. Upon submitting the specimen which contained them to a more careful examination, I found, in different parts of it, five completely formed Acari, all of which were much smaller than those found in cheese, brown sugar, and damp bran, specimens of which I obtained for the purpose of comparison.

The subject to which I have to invite the attention of the Society this evening is one of no modern origin, the name of Hippocrates, amongst others of the fathers of medicine, being commonly associated with it. There is, indeed, perhaps no branch of medical inquiry whose history dips more deeply into the obscure pages of antiquity. The influence of weather upon disease and mortality has been acknowledged as a potent external force in every age, from that eminently speculative and credulous period when physicians professed to receive their diagnostic as well as their therapeutic inspirations from the stars, down to our own day. And yet there is perhaps no question in the whole cycle of medical sciences which has made slower progress than the one we have now to consider. People believe that the weather affects them. They speak of its influence, sometimes commendingly, more frequently with censure, on the most trivial occasions; but beyond a few commonplace ideas, the result of careless observation, or perhaps acquired only traditionally, they seldom seek a closer acquaintance with the subject. Our language teems with medico-meteorological apophthegms, but they are notoriously vague. The words which are most commonly employed to signify the state of the weather at any given time, possess a value relative only to the sensations of the individual uttering them. The general and convertible terms—bitter, raw, cold, severe, bleak, inclement, or fine and bracing, convey no definite idea of the condition of the weather; nay, it is quite possible that we may hear these several expressions used by different persons with reference to the weather of one and the same place and point of time. In order, then, to render medico-meteorological researches more trustworthy, we must be careful to employ, in the expression of facts, such symbols only as have a corresponding value in every nation.

The whole southern part of Arran forms a field by itself, and whatever may be the deeper connections of the agencies that have fashioned the north and the south of the island, the result is a trappean area to the south, as distinct as if it lay in another hemisphere from the north, with its granitic nucleus, and encompassing rings of stratified rock.

This district is little visited, and is almost, if not quite, undescribed; it presents, however, much beautiful scenery, and for the geologist, problems of extreme difficulty and interest, which deserve more attention than they have got.

It may be divided into two belts of tilled land and moorland, above which are the hill tops. This division corresponds roughly to three regions, the lowest chiefly of sandstone, the middle where felstone prevails over the sandstone, and the highest of greenstone.

In the construction of the animal kingdom, Nature shows herself always provident and saving, both in the amount of organic matter which she uses, and in the complexity of the organic structures which she moulds out of that matter. She never employs any superfluous quantity of material, nor any superfluous quality of mechanism. If a low type of structure in an organ is sufficient for the due performance of the given function of that organ, she never resorts to a higher or more complex type. She does not build organs or animals with the higher organic types of nerves, capillaries, lymphatics, &c., when these organs or animals do not require for their function, or for their life, the special physiological action of nerves, capillaries, or lymphatics. She expends no unnecessary workmanship upon the vital machinery which she employs, nor does she ever add to it any unnecessary pieces of organic apparatus.

When occupied several years ago in studying the fluid and gaseous cavities in minerals, my attention was drawn to certain remarkable formations in perfectly transparent specimens of calcareous spar. These formations were of two kinds—the one apparently of vegetable origin, and the other obviously mineral.

It does not always happen that the memory of inquirers into nature, who have the merit or the fortune to strike first into a right path, is cherished as it deserves. This remark applies forcibly to the eminent person, whether regarded as a physiologist or as a physician, of whose life aud labours a brief memoir is now laid before the Society. The name of Robert Whytt was familiar to his contemporaries both at home and abroad. Increase of distance should hardly yet have dimmed its lustre. Yet, in proportion as the views which he initiated have expanded more and more in growing to maturity, the less and less is heard of their author. Biography—which never did Whytt great justice—begins already to put him aside. A few particulars of his life, with a catalogue of his works, have hitherto been common in books of that description, principally in those of Germany and France. In some newer French biographies his name has dropped out. But of a late Edinburgh Biographical Dictionary, extending to not a few volumes, while restricted to the lives of eminent Scotsmen, it will hardly obtain credit that an early luminary of the rising University, conspicuous among the European leaders of medical science during a busy period of the eighteenth century, should, amidst a cloud of mediocrity, be there sought for in vain.

In the paper which I had the honour to read before the Society last winter, I stated the reasons, drawn from history and from comparative philology, which exist for concluding that the Brahmanical Indians belong to the same race as the Greek, the Latin, the Teutonic, and other nations of Europe. If this conclusion be well-founded, it is evident that at the time when the several branches of the great Indo-European family separated to commence their migrations in the direction of their future homes, they must have possessed in common a large stock of religious and mythological conceptions. This common mythology would, in the natural course of events, and from the action of various causes, undergo a gradual modification analogous to that undergone by the common language which had originally been spoken by all these tribes during the period of their union; and, in the one case as in the other, this modification would assume in the different races a varying character, corresponding to the diversity of the influences to which they were severally subjected.

I have already endeavoured to prove that Auroræ and Earth-currents, far from producing magnetic disturbances by their direct action, are themselves only secondary or induced currents, generated by those small but abrupt changes of the earth's magnetism which constitute such disturbances. The proof of this statement was in the first place derived in a general manner from the fact that during the notable magnetic storm of August and September 1859, all the elements of the earth's magnetism at Kew remained for many hours on one side of their normal positions, while, on the other hand, the earth-currents observed during that time by Mr C. V. Walker had their direction reversed every two or three minutes.

It is certain that the unities which constitute aeriform media, when they have been fully separated from each other by an adequate temperature, and relieved from excessive pressure, are all equal to each other in volume, whatever the aeriform may be, either singly or in couples, or in pairs of couples, double pairs of couples, &c., giving such ratios as 1: ½: 4: 8, &c.

1. The experiments to which I shall have to refer in this paper were all made above ten years ago. A brief report of the general results, so far as they were then obtained, was made to the British Association in 1852, at whose expense the instrumental apparatus had been provided. The causes of the delay which has occurred in the publication of the numerical results will be presently explained.

The following pages contain an account of a few double-star measures which, by the kind permission of J. W. Grant, Esq., of Elchies, in Morayshire, I was enabled to make there in September 1862, with his large and equatorially mounted refracting telescope; and as that instrument is altogether the best and most powerful of its kind which has hitherto been erected in Scotland, such a trial of its capabilities, and the first which has been published, will undoubtedly have a peculiar interest for the Royal Society of Edinburgh.