The author's “Observations” relate mainly to the Microscopic Anatomy of the reproductive tissues and corpuscles of about fifty Lichenicolous Parasites—apparently new species—referable partly to the true Fungi, and partly to the Fungo-Lichenes. These parasites, themselves microscopic, have accumulated in the author's Herbarium during the last twelve or fifteen years: or were examined by him while determining the species of various British and foreign Lichen-collections submitted for that purpose during the same period.

In a paper recently communicated to the Society by Mr Main and myself, we showed that when nitrogen and aqueous vapour are passed over magnesium ammonia is formed. We took for granted the theory of the reaction to be that the magnesium decomposes the aqueous vapour, and that the hydrogen thus produced, when in the nascent state, combines with nitrogen and forms ammonia. In a discussion which followed the reading of the paper, Mr Dittmar maintained that such was not the theory of the reaction, but that nitride of magnesium is first produced, and then decomposed by the aqueous vapour into ammonia and magnesia.

The author gave the chief results of 120 experiments upon frogs, rabbits, and dogs, as follows:—

1. He showed, by novel methods of experimentation, that the inferior cardiac branches of the vagi are—as the brothers Weber. pointed out—inhibitory nerves of the heart, and that they cannot in any sense be regarded as motor nerves of the heart, as maintained by Schiff, Moleschott, Lister, and others. The experiments bearing on this question were performed in 1866–67.

In the first part of the paper I adduce probable, or prima facie, evidence in favour of the theory that the power which produces voluntary motion is not derived solely, nor even chiefly, from the decomposition of the muscular tissues, as has been generally, if not universally, held by recent investigators, but is derived primarily and principally from the decomposition of the cerebral tissues; and second, that this decomposition of the brain is effected by a direct voluntary mental effort.

The immediate allies of the Nemerteans are evidently the Planarians, and Ehrenberg's class Turbellaria, as now amended, is therefore a very natural one. There is, however, a considerable divergence between the two groups; and since it is only through the Planarians that the Nemerteans can in any way be linked on to the Trematoda, it is found that there is little structural resemblance between the two last-mentioned types. The various parts of the organism in the Trematodes and Planarians (through which the connection of the Nemerteans with the former may be supposed to occur) were contrasted, and their homologies explained. The structural relations of the Planarians and Nemerteans were then considered; and, thirdly, the connections of the latter with the higher Annelids were alluded to.

When the wood of the bebeeru tree is subjected to a process similar to that recommended in the British Pharmacopœia for the separation of bebeerine from the bark, a mixture of several alkaloids is obtained.

In this memoir the authors specially describe the properties of one of these alkaloids, to which they have assigned the name Nectandria and the formula C20H23NO4. (Bebeerine, according to V. Planta, has the formula C18H21NO3). Nectandria is obtained by treating the mixed alkaloids obtained from the wood with chloroform, in which it is abundantly soluble.

I. An account was given of the dimensions of the estuary, in respect of length, width, and depth; and also of the general direction of the axis of the estuary.

II. It was next shown that the formation of the estuary was probably due to the great geological fractures and dislocations which had taken place in this part of Scotland, inasmuch as the direction of these was parallel, or nearly so, to the axis of the estuary, and as the downcasts in the adjoining counties on the north and the south were all towards the estuary, thus producing a trough or valley, deep enough to be entered and filled by the sea.

The principal object of the paper is to investigate how far the singular phenomena exhibited by the tails of comets, and by the envelopes of their nuclei, the shrinking of their nuclei as they approach the sun, and vice versâ, as well as the diminution of period presented by some of them, can be explained on the probable supposition that a comet is a mere cloud of small masses, such as stones and fragments of meteoric iron, shining by reflected light alone, except where these masses impinge on one another, or on other matter circulating round the sun, and thus produce luminous gases, along with considerable modifications of their relative motion. Thus the gaseous spectrum of the nucleus is assigned to the same impacts which throw out from the ranks those masses which form the tail.

The object of this paper is to consider the mathematical value of Hegel's discussion of the fluxional calculus. This discussion, as contained in several notes in the “Logik,” professes to evolve the true principle of the calculus in a form free from the inconsistencies of the usual processes, and to show how this principle may be rendered useful in the solution of problems. To clear the way for this new theory, Hegel engages in a sharp polemic against the expositions of several parts of the calculus given by Newton and others.

In papers which the authors have already communicated to this Society, they have shown that there exists a very marked difference between the action of bases containing nitrogen as a triad and those in which that element is pentad. This result was obtained from an examination of the physiological action of substances having an unknown and complex constitution. It appeared to be necessary to institute a series of experiments with bodies having a simpler and fully known constitution. For this purpose, the salts of ammonia, tri-methylamine, and tetra-methyl-ammonium were selected. A comparison of the structural formulae of the hydrochlorates of these bases shows that tri-methylamine stands in the same relation to the salts of tetramethyl-ammonium as strychnia to the salts of methyl-strychnium.

The subject of range of temperature has been divided by meteorologists into the two main heads of Diurnal and Annual range, the former being measured by the variation of temperature between the warmest and coldest hours of the day, the latter by the difference of temperature between the warmest and coldest months of the year.

For a study of diurnal range we should require a series of observations for every hour of the day and night from all parts of the earth, and the places where such laborious observations have been made are as yet very few; but the returns of daily and monthly temperatures now obtainable from all countries are sufficient for a tolerably complete study of the simpler head of annual range.

The following note refers to some experiments instituted at the request of Mr Dewar, who asked me to determine the polarisation of the Palladium electrodes whose singular behaviour he recently described to the Society.

I had just obtained one of Sir W. Thomson's most recent forms of quadrant electrometer, and it occurred to me that this must be the proper instrument for determining polarisation, as its indicacations are not affected by electric resistance, and give directly—that is, without assuming the truth of Ohm's law for reverse electromotive forces, and the consequent necessary determinations of resistance—the quantities required.

In offering these remarks on the causes of volcanic action, I take it as proved that volcanoes are in communication with a reservoir of heat, occupying the centre of the earth: which heat, however, the earth is gradually, though very slowly, losing; partly by volcanic eruptions, partly by hot springs, and partly by the slow conduction of heat towards the surface through the strata.

I also take it as proved, that the earth is not fluid but solid throughout; or, at least, that its solid crust is of such thickness that the earth is to be regarded for all purposes as a solid body. Consequently the production of lava—that is to say, the liquefaction from heat of a small portion of the solid mass of the earth—is a strictly local occurrence; this is sufficiently proved by the well-known fact, that the lava stands at different levels in different volcanic craters, even when they are in eruption at the same time, and very near each other: as in the case of Mauna-Loa and Kilanea, in Hawaii (Scrope on Volcanoes, p. 262), which would be impossible if there were any free hydraulic communication between the different reservoirs of lava.

In this paper the author described a number of observations which appear to demonstrate that the fatal action of certain doses of physostigma may be prevented by the administration of atropia.

The following plan was adopted for the investigation:—After the minimum fatal dose of each poison bad been approximately determined for rabbits and dogs of different weights, a fatal dose of one of the poisons was administered along with a certain dose of the other, and, if death did not result, the same animal was subsequently killed by a dose of one of the poisons equal to or less than that given in the combination.

In a previous paper, presented to the Royal Society of Edinburgh in December 1849, and read on the 5th of February 1850 (Trans. vol. xx.), the author deduced the principles of thermodynamics, and various properties of elastic fluids, from the hypothesis of molecular vortices, under certain special suppositions as to the figure and arrangement of the vortices, and as to the properties of the matter which moves in them. In subsequent papers, he showed how the hypothesis might be simplified, by dispensing with some of the special suppositions.