From a peculiar change of colour observed in the electrolysis of a solution of copper-cobalt potassium sulphate, the author was recently induced to make some experiments on the behaviour of cobalt sulphate solution when electrolysed in such a manner that the reducing product of the decomposition could not act on the solution. For this purpose a divided cell was used, so that the two electrodes were practically in separate vessels. The apparatus will be fully described in a future communication.

In this short paper I wish merely to give a summary of the chief results of experiments made by me in February and March last in the Physiological Institute of Berlin. Du Bois Eeymond has recently made an elaborate investigation of the galvanic polarisation of muscle. Many years ago he made similar observations on nerve. The question which occurred to me was, How does tetanus affect the amount of polarisation in nervel? Apparently there has been no previous work at this subject. It is not necessary to describe here the arrangements used, nor the manner of making the observations, as a detailed aecount, with discussion of the facts brought out, will appear in the Journal of Physiology. When a current is passed through a living nerve, the polarisation produced may be either negative or positive. When it is negative, the polarisation current is, of course, in the opposite direction to the polarising current. Positive polarisation gives a current in the same direction as the polarising stream. It depends upon the “density” of the polarising current, and upon the time of flow, whether the deflection due to the polarisation is purely negative, purely positive, or of double sign. When it is of double sign, there is first a negative kick, which is followed by a more persistent positive deflection. As a matter of fact, there is every ground for believing, that in general the two polarisations exist side by side in the polarised nerve.

The noises considered in this paper are uniform, continuous noises, such as the fricatives of articulate speech: f, θ, ς, 묪, χ &c. These sounds are considered by the author to stand in a similar relation to musical tones as lights with continuous spectra do to lights with bright-line spectra. Methods were proposed for analysing these uniform continuous noises, and also for imitating them by synthetic means.

The end-organs of the special senses are all built up on the same type. The history of their development from simple ectodermic cells suggests that similar agencies have been at work to produce them. Both sapid and odorous substances, and indeed all gaseous and liquid molecules, are now known to be in constant vibration, and this vibration is more or less characteristic of the substance examined.

By a number of observations made incidentally in the preparation of two of the double salts referred to in the heading, namely, the compounds of sulphate of potash with sulphate of magnesia and sulphate of ferrous oxide respectively, I had long come to suspect that these two salts at any rate are not perfectly stable in opposition to water. To settle the question, I have caused Mr James Eobson and Mr Andrew Hodge, two young chemists working in my laboratory, to inquire into the matter by systematic experiments. These were, in general at least, conducted according to the following scheme: —Starting from a known weight of sulphate of potash, this was dissolved in a proportion of hot water,* less than sufficient to hold the intended double salt in solution after cooling; there was then added a known weight of the di-valent sulphate amounting to exactly 1 or 1·1 or 1·2 … 1·5 times MgO or FeO per 1K2O used, the solution filtered hot into a basin, allowed to crystallise, and the crop of crystals produced examined.

Mr H. A. Webster, Mr John S. Yeo, Mr John Cockburn, Dr A. S. Cumming, and Mr J. W. Capstick were balloted for and declared duly elected Fellows of the Society.

This paper dealt only with cases in which the electromotive force used is insufficient to produce decomposition. In such cases the electrodes act as condensers. But the observed law of variation of current-strength with time is not exactly that which holds in the charging of ordinary condensers. The author showed that the deviation could be largely accounted for by the continual increase of transition resistance, the existence of which lie proves in a separate paper on that subject.

The question of the existence of true transition resistance at the surface of certain electrodes in given liquids has been in debate for many years, but has never yet been conclusively settled. It is admitted universally that in certain cases such resistance does occur, as, e.g., when a non-conducting oxide is formed on the surface of the metal; but the point in dispute is whether or not it occurs when no direct chemical action takes place between the metal and the products of electrolysis, or between it and substances dissolved in the liquid.

Being convinced that a thorough examination (both from a chemical and physiological point of view) of the various problematical organs of the Invertebrata -will throw much light on their physiology and their relationship to the Vertebrata, these investigations have been undertaken with that object in view.

The excretory system in this species has never been adequately described; it presents an extremely interesting condition from a morphological point of view. There are four well-developed nephridia in somites 6–9, inclusive. Each of these commences by an internal aperture or nephrostome, and consists of a bent tube or loop, the inner side (the side nearer the median plane) of the loop being connected with the nephrostome, while the outer passes downwards and opens into a longitudinal tube common to all the four nephridia of a side. Four openings, corresponding to the four nephridia, place the longitudinal tube in communication with the exterior; these openings are close behind the upper ends of the 2nd to the 5th uncinigerous tori respectively; the 1st uncinigerous torus being in the 5th somite. The longitudinal tube is continued backwards on each side through somites 10–13, representing four more coalesced nephridia; but in this region there are neither internal nor external openings, nor any loops similar to those in the more interior region; the longitudinal tube is simple, almost cylindrical, showing slight indentations between the successive somites, which mark where the successive nephridia have coalesced. The outer side of the whole longitudinal tube is in contact with the ventral longitudinal muscles, while the upper and inner side is beneath the oblique muscles. The internal openings already mentioned are situated immediately behind the notopodial fascicles of setae of somites 5–8 inclusive. The longitudinal tube extends into the 5th somite, but I could not find there an external opening. Behind the 1st to the 4th somites are traces of incomplete septa, of which that behind the 4th is the most complete. Attached to the front of the latter septum is a nephrostome, but I could not trace any connection between this and the part of the tube in the 5th somite. There are two other well-marked nephrostomata attached to the septa behind somites 2 and 3, and these openings lead into tubes seen in somites 3 and 4. I could not find external openings in the two latter somites. There are thus eleven nephridia represented altogether,—three rudimentary, in somites 3, 4, 5; four perfect, in somites 6–9; and four imperfect, in somites 10–13; the eight posterior being all in communication, their distal parts having fused to form a longitudinal tube. This is the first case in which such a longitudinal coalescence of nephridia has been discovered, and its morphological similarity to the condition in Vertebrates is obvious.

Great diversity of opinion exists as to the frequency of the occurrence of albuminuria in healthy people, and elaborate inquiries have led different observers to conspicuously contradictory conclusions. Posner has said that his observations satisfy him that traces of albumen exist in every normal urine, and may be demonstrated if sufficiently delicate methods are employed. One of the most distinguished authorities on the subject, Dr Senator of Berlin, says that his observations supply good reason why he should consider it not improbable that, if we were to examine the urine for long periods at different hours of the day, and with, great care, we should sooner or later find it to contain albumen in the case of every healthy man. Dr Kleudgen, in the course of a special study of albuminuria in relation to epilepsy, came to the conclusion that traces of albumen could be demonstrated in any urine above a certain degree of concentration. Dr de la Celle de Chateaubourg found albumen in the urine of 592 out of 701 healthy people whom he examined, that is in 84 per cent. Dr Capitan found that among 98 French soldiers 44 or 44·9 percent, had albuminuria.

During the last ten years numerous investigations have been made to ascertain whether ordinary (i.e., non-specific) bacteria exist in the tissues of apparently healthy, living animals. As a result of these inquiries, it has been clearly shown that while there is no evidence of the existence of bacteria, under ordinary circumstances, in the blood of the higher Vertebrata, there is abundance of evidence of their presence in the blood of some fishe

Among the many and various controversies to which the geological study of the great chain of the Alps has given rise, not the least interesting is that which has reference to the origin of the beautiful lakes which occur most numerously in the lower reaches of the mountain valleys. None of the theories hitherto set forth seems to me to explain the origin of these remarkable basins, and in place of these I now venture to adduce one of my own, which has been suggested by some years's; observations on the Tertiary and Quaternary accumulations of the valley of the Po. Of course, it will be understood that I am far from denying that lacustrine basins may owe their origin to many various causes; and for lakes in general I am inclined to adopt some such classification as the following:

Twenty-seven years ago the writer submitted to the Eoyal Society of Edinburgh a paper on the minute oscillations of flexible pendulums, in which some new general laws were expounded. He proposes now to consider one case of the phenomenon more in detail.