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which M. Chaix has added his experiments upon the proportion of solid matter contained in the water of the Arve.

On the 27th of November of last year occurred that remarkable rain of meteors, which seemed to confirm the hypothesis that shooting stars are produced by the disintegration of comets. M. Plantamour gave to the society the data for the solution of the question, to which the attention of the society was again directed by M. E. Gautier, in the course of a notice of the presumed discovery of the comet of Biela by an astronomer of Madras.

I complete the notice of astronomical researches by mentioning the remarkable instance communicated by M. Thury of astronomical visibility. He observed, by means of his small refractor, with great clearness, on the night of the 15th to 16th of June, the star Antarès and the small blue star near it.

Want of space permits me merely to recall to your memory, without analyzing it, the communication of M. Soret in regard to his comparative researches between thermal solar radiation and that of a body heated in the oxyhydric flame. These researches, which modify the assertions of P. Secchi in regard to the temperature of the sun, have been published. I would say here, that it is our custom, in our annual account of the proceedings of the society, to confine ourselves almost exclusively to communications which have not been laid before the public. I give, once for all, this explanation, to account for the more or less brief notice of some of the subjects which have been discussed at our sessions.

M. Wartmann discussed the theory of the perception of color, which admits three systems of nerves, corresponding to the three fundamental colors, and opposed to this theory certain observed facts; in particular, the fact that certain Daltonians do not perceive color, but only a contrast of light and shade of different intensities.

Information in regard to the aurora borealis has, from time to time, been sent to me by observers of this phenomenon and by savans interested in the subject. I have communicated to the society the principal inferences drawn from a work of M. Boué, upon the concordance of austral and boreal auroras which he sent me in a letter, and also those from the researches of M. Lovering, who has united in a catalogue more than 12,000 observations of auroras.

M. Marignac has given us the result of his experiments upon the identity of the heat of fusion and the heat of solution. The temperature of solution of a body whose point of fusion is very low was observed during the cooling, and particularly as it passed the point of fusion. There was no sudden change, nothing anomalous, as it passed this point; and M. Marignac therefore concluded that the heat of fusion is identical with that of solution. For this experiment a solution of spermaceti in alcohol was used; the point of fusion was at 48° C. The

substances which meet the conditions required by these researches are few in number.

M. E. Ador has presented to the society a summary of his researches in regard to the radical of phtalic acid.

I close the account of our labors in physical science by mentioning the oral summary given by M. Casin of some of his researches, already printed, which he has presented to the society.

I also recall that Professor Gautier in numerous reports, several of which have been published in the archives, has informed us of various astronomical investigations, and in particular of those of M. Huggins of stellar spectra in regard to the direction of the movement of stars in relation to the earth.

2. The natural sciences.-Geology and paleontology have so much in common, that it seems to me quite natural to mention in connection what relates to these two sciences.

I would remind you that M. A. Favre presented an article upon phos. phates, and their beds, and that M. E. Favre made the society acquainted with the recent works upon the structure of ammonites.

The boring of the Gothard cannot fail to interest geologists. Specimens of the different rocks encountered will be preserved in their order of succession. M. A. Favre, in making a communication to the society upon this subject, suggested the request for a set of these specimens for the Museum of Geneva.

M. Ed. Sarasin presented an article, prepared with the assistance of M. Fuchs, upon the sources of the petroleum of Câmpina, in Wallachia. This article assigns to petroleum an eruptive origin, and assimilates it to the hydrocarbons disengaged during volcanic phenomena. This hypothesis led the authors to expect that they would find in beds of petroleum a distribution analogous to that of metalliferous strata; their anticipations were confirmed by the discovery of an orientation, following two parallel lines, in the petroleum-emanations of the plateau of Câmpina.

M. de Saussure, on his return from a visit to Naples, gave us a description of the crater of Vesuvius, then in eruption, (see the Journal of Geneva,) and also presented the society with several other communications, upon various subjects, which have already been published.

M. Dor exhibited to us three skulls of the lacustrian period, recently discovered. Two of these skulls belong to the stone age, and are therefore very valuable, on account of the rarity of such specimens, a rarity probably due to the custom of burning bodies. They are skulls of the ancient Helvetians, a Celtic race. The large size of one of them shows that the stature of the man of the stone age was greater than has been supposed. The third is the skull of a child of the bronze age.

Under the head of "animal physiology" should be recorded the researches of M. Prevost upon the section of the cord of the tympanum. Contrary to the opinion first announced by M. Vulpian, and afterward

modified by this scientist's own observations, M. Prevost found that the cord of the tympanum is not entirely lost in the lower maxillary gland, but sends threads to the tongue. Employing the Waller method, he divided the tympanum-cord of dogs, cats, &c., and a few days after found wasted nervous tubes in the terminal branches of the lingual.

M. Prevost has given us the results of some experiments upon the nerves of taste. These are opposed to the hypothesis that the fibers, of the lingual nerve which transmits the gustatory impressions, pass through the spheno-palatine ganglion. In fact, the amputation of two spheno-palatine ganglions, accompanied by the section of the two glossopharyngeal nerves, does not alter the transmission of the gustatory sen sations in the parts moved by the lingual nerve.

Under the head of physiology should also be mentioned a communication concerning the investigations of the congress of medical men at Lyons, in regard to the supposed cause of the fevers which justly give to the climate of the Dombes character for insalubrity. In this communication the intermittent fever of these regions is attributed to the spores of a conferva, very abundant in the marshes of that neighborhood, which rise in the air, with the water evaporated.

M. Lombard, in regard to a subject upon which he had before ad dressed the society, presented the fact that pulmonary consumption or phthisis decreases with altitude, and mentioned Davos station, at an elevation of 1,556 meters, as having been found particularly favorable to persons affected with this disease.

In natural history proper, M. V. Fatio has given an account of his researches in regard to the development of the black salamander, which differs greatly from that of the spotted variety. The black salamander produces only two living progeny, although at the same time the ovary contains a large number of eggs. Four of these eggs are developed at the expense of the others, which are decomposed and serve them as nourishment; after a time the development of two of the four embryos is arrested, and they in turn serve as nutrition for the last two, which alone survive, and are born after undergoing various metamorphoses. M. Lombard exhibited to the society a blind fish from the Mammoth Cave of Kentucky, sent to the Museum of Geneva by M. V. Lombard. Vegetable physiology has been represented, first, by a communication from M. Rissler, upon the nutrition of plants. M. Rissler reminded the society that he had before presented some researches upon the double part played by the humus, which assists the dissolution of the mineral substances useful to the plant, and also furnishes portion of the carbon it contains. His views were opposed to a subsequent memoir upon the same subject, to which he drew attention, by M. Grandeau, in which M. Rissler's researches are not mentioned, and according to which the part played by the humus consists only in dissolving the nutritive substances.

M. de Candolle, in noticing the appearance, recently observed, of Al

gerine plauts in France, expressed his doubts as to their definite estab lishment, and gave some examples of exceptional and temporary devel opment of plants.

While exhibiting to the society a flower of the orchid order, the Angræcum sesquipedale, a plant which is a native of Madagascar and only very recently introduced into Europe, M. E. Boissier gave us the views of Darwin in regard to the mode of fecundation of this flower. It is remarkable for a spur of extraordinary length, the elongation of which Darwin considers must be the consequence of the length of the proboscis of a certain butterfly which is still unknown, and which would be the only insect which could determine the fecundation of this orchid. In fact, in all the flowers provided with short spurs, as this butterfly touches the nectar with the end of its proboscis, and does not introduce the latter entirely, it does not carry off pollen with its head. Such flowers, in consequence, do not participate in the fecundation of the others, and tend to disappear. M. Boissier made some objections to this theory, which he considers insufficiently founded upon observation and even logical deduction.

M. Müller claimed to have proved in a striking manner the intimate mingling of the two distinct forms of the ordinary cowslip or primrose, and gave this fact as a remarkable example of dimorphism. He recalled to mind that if fecundation takes place under the most favorable condi tions, it must be between flowers of opposite form.

A communication was made to us by M. Lichtenstein, of Montpellier, upon the ravages caused in vineyards by the Phylloxera vastatrix. In the same family of plants certain species seem to be spared by this disease. Thus, although the European vine transported to America may be affected by it, it does not attack the vine indigenous to America. M. Lichtenstein has not observed in Switzerland the injurious species of Phylloxera.

Lichens, and the theory of M. Schwandener, according to which they have been assimilated to a combination of mushrooms and sea-weeds, have been the subject of a communication from M. Müller. It is true that the anatomic structure of lichens exhibits the superposition of green cells called gonidés, and this is analogous to that of sea-weeds, also a felty tissue containing no chlorophyl, in which it resembles the organization of mushrooms; but still we never find among the lichens the effects produced by the parasitism of the mushrooms, and there exist among them forms of fruit and spores never found among the mushrooms. M. Müller does not accept this theory, and sees in lichens a dimorphism of which the two terms are: 1. A complete state, known under the name lichen. 2. An incomplete state, never producing fruit, and which corresponds to the lichen which grows in an isolated condition.

M. Duby informed the society that an anomalous moss had been sent to him from New Caledonia. He described two characteristics found in no other known moss, which establishes a new genus.

The name Mr.

Duby has given to this genus is Sunodontea, and the species has been called Spathoidea.

M. de Candolle has stated to the society that a plant, the Linnea borealis, whose existence in our vicinity has been unknown since De Saussure found it growing upon the Voirons, had been discovered by M. P. Privat, upon the pass of Oche.

M. W. Barbey presented to the society an article upon plants of the genus Epilobium. In this genus there are some especial difficulties in the determination of species, concerning which there is great uncertainty, notwithstanding numerous investigations. The seed ought to furnish the best characteristics for determination, but the Epilobia multiply readily by suckers, which favors the permanence of the hybrid specimens which abound in this genus. These plants are found in great abundance in New Zealand.

M. Humbert has presented several very interesting communications upon some publications relative to natural history, particularly upon the work of Hæckel on calcareous sponges.

I ought also to mention several reviews, presented by different members, of published works; among others, that of M. Ernest Favre, of the work of M. Barrande upon the silurian formation of Bohemia, and those of M. Micheli, of the new edition of the treatise on botany of M. Sachs, and of a work of M. Krauss, professor of botany at Erlangen, upon the coloring matter of chlorophyl.

If I do not dwell upon communications of this kind, it is because, in the reports of the president, as I have said before, it is customary to confine attention principally to original papers; but I cannot terminate this report without special notice of the communication, so full of interest, made by M. Alphonse de Candolle to the society, in its session of June, 1873, the last at which I had the honor to preside. In announcing the publication of the seventeenth and last volume of the Prodromus systematis naturalis regni vegetabilis, he gave an historical summary of this great and important work. I willingly extend this detailed account of what I consider one of the most glorious memorials of the science of Geneva.

The idea of making a complete revision of the vegetable kingdom. was conceived by Augustin Pyramus de Candolle, during the last years of his residence in Montpellier, about 1813 or 1814.

The end he proposed to himself then, especially, was to improve and diffuse the knowledge of the natural system he was the first to make use of, in an important flora, (Flore française, 1805,) and the principles of which he unfolded in his elementary treatise, (1813.) He began with some monographs of families, very carefully elaborated, which he published in two volumes called Regni vegetabilis systema naturale, (1818 and 1821.) He soon saw that to treat every family in this way would be beyond the powers of one man, and would require a great deal too much time, even supposing, as was then believed, that the number of species

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