in the plant. 'It may either be formed directly from glucose, ammonia (or nitrates) and sulphates, or it may be a transitory product between protein-decomposition and reconstruction from the fragments.' 1 In the remarks I made to the Chemical Society I ventured to express my conviction that the chemical processes which took place under the influence of protoplasm were probably of a different kind from those with which the chemist is ordinarily occupied. The plant produces a profusion of substances, apparently with great facility, which the chemist can only build up in the most circuitous way. As Victor Meyer has remarked: 'In order to isolate an organic substance we are generally confined to the purely accidental properties of crystallisation and volatilisation.' In other words, the chemist only deals with bodies of great molecular stability; while it cannot be doubted that those which play a part in the processes of life are the very opposite in every respect. I am convinced that if the chemist is to help in the field of protoplasmic activity, he will have to transcend his present limitations, and be prepared to admit that as there may be more than one algebra, there may be more than one chemistry. I am glad to see that a somewhat similar idea has been suggested by other fields of inquiry. Professor Meldola 3 thinks that the investigation of photochemical processes may lead to the recognition of a new order of chemical attraction, or of the old chemical attraction in a different degree.' I am delighted to see that the ideas which were floating, I confess, in a very nebulous form in my brain are being clothed with greater precision by Loew. 46 3 In the paper which I have already quoted, he says of proteids: They are exceedingly labil compounds that can be easily converted into relatively stable ones. A great lability is the indispensable and necessary foundation for the production of the various actions of the living protoplasm, for the mode of motions that move the life-machinery. There is a source of motion in the labil position of atoms in molecules, a source that has hitherto not been taken into consideration either by chemists or by physicists.' But I must say no more. The problems to which I might invite attention on an occasion like this are endless. I have not even attempted to do justice to the work that has been accomplished amongst ourselves, full of interest and novelty as it is. But I will venture to say this, that if capacity and earnestness afford an augury of success, the prospects of the future of our Section possess every element of promise. The following Papers were read : 1. On a False Bacterium. By Professor MARSHALL WARD, F.R.S. The author has isolated from the Thames a form which gives all the ordinary reactions of a bacterium in plate-cultures and tube-cultures in gelatine, agar, potato, broth, milk, &c. It is a rod-like form, 1 μ thick, and up to 2-4 μ long, stains like a bacillus, and cannot be distinguished from a true Schizomycete by the methods in common use. On cultivating it under high powers-one-twelfth and one-twentieth oil immersions-from the single cell, however, it is found to form small, shortly branched mycelia the growth and segmentation of which are acropetal. This turns out to be a minute oidial form of a true fungus. Its true nature can only be ascertained by the isolation and culture through all stages from the single cell, according to the original methods of gelatine cultures of Klebs, Brefeld, and De Bary which preceded and suggested the methods employed by bacteriologists; and the facts discovered raise interesting questions as to the character of alleged branching' bacteria on the one hand, and the multiple derivation of the heterogeneous group of micro-organisms, termed bacteria in general on the other. 1 Loc. cit., 64. 2 Pharm. Journ., 1890, 773. 2. On the Archesporium. By Professor F. O. BOWER, F.R.S. Professor Bower pointed out that the recognition of the archesporium as consistently of hypodermal origin cannot be upheld, and quoted as exceptions Equisetum, Isoetes, Ophioglossum, and especially the leptosporangiate ferns. He laid down the general principle that the sporangia, as regards their development, should be studied in the light of a knowledge of the apical meristems of the plants in question. Where the apical meristems are stratified, the archesporium is hypodermal in the usual sense; where initial cells occur, the archesporium is derived by periclinal divisions of superficial cells. Intermediate types of meristem show an intermediate type of origin of the archesporium. He cited as an illustrative case that of Ophioglossum, admitting that the hypodermal band of potential archesporium, which he had previously described, does not occur always or in all species. But so far from thus giving up the case for a comparison with Lycopodium, he holds that as Ophioglossum has a single initial cell in stem and root, it would be contrary to experience to expect or demand a hypodermal archesporium. 3. Note on the Occurrence in New Zealand of two forms of Peltoid1 Trentepohliacea, and their relation to the Lichen Strigula. By A. VAUGHAN JENNINGS, FL.S., F.G.S. The Trentepohliaceae which form epiphyllous cell-plates are at present known only from the tropics (with the exception of two imperfectly developed forms in the northern temperate zone). They have been recorded from S. America (Bornet), India and Ceylon (the Mycoidea parasitica of Cunningham and Marshall Ward), and the East Indies (Karsten), but not up to the present time from New Zealand. The present paper gives a summary of previous literature, and describes two forms found by the writer in New Zealand. (1) Phycopeltis expansa (new species). This species forms wide-spreading yellow cell-plates on the leaves of Nesodaphne in the North Island (Rotorua), and in the South Island (near Picton). Sporangia of two kinds: (a) enlarged cells of the disc; (b) borne singly on a hooked pedicel supported on a single basal cell. The plant is often associated with brown fungus hyphae growing between the cellrows, but not affecting the growth of the alga. On the other hand, when attacked by different hyphæ, the result is the formation of the lichen Strigula, which in Ceylon was shown by Ward to have for its algal element the Mycoidea parasitica, Cunn. (2) Phycopeltis nigra (new species).—The second form is found also on leaves of Nesodaphne with the Phycopeltis above described, and alone on fronds of Asplenium falcatum. Sporangia in the disc are present, but no trace of sporangia on pedicels is observed. The plant always forms narrow, radiating, and branching bands, never circular discs: the margins often irregular and tending to break into filaments. There are two distinct varieties:-(a) a comparatively large-celled form with barren hairs well developed; (b) a small-celled type entirely devoid of hairs. The most remarkable feature, however, is the colour. On the leaf the plant appears perfectly black, and by transmitted light has the olive-green colour characteristic of many fungi, quite different from any of the ordinary Trentepohlias. The plant is never attacked by fungus hyphæ, and never takes any part in lichen formation, even when on the same leaf with Phycopeltis expansa and the associated Strigula. Term used for those which form cell-plates (type Phycopeltis), as distinguished from cell-filaments (Trentepohlia). FRIDAY, SEPTEMBER 13. The following Papers were read :— 1. Experimental Studies in the Variation of Yeast Cells. By Dr. EMIL CHR. HANSEN, Copenhagen. The author gave an account of his earlier and more recent investigations. Among the latter he especially dwelt on those in which, by one treatment, varieties were produced that gave more, and by another treatment less, alcohol than their parent cells. He pointed out that the observed variations could be grouped under certain rules. From his researches on the agencies and causes to which variation is due, he found that temperature was the most influential external factor.1 2. On a New Form of Fructification in Sphenophyllum. Graf Solms gave a brief sketch of the history of our knowledge of the fructification of the Carboniferous genus Sphenophyllum. He described the type of strobilus originally named by Williamson Volkmannia Dawsoni, and subsequently placed by Weiss in the genus Bowmanites; this fructification has recently been shown by Williamson and Zeiller to belong to Sphenophyllum. The author proceeded to give an account of a new form of strobilus recently obtained from rocks of Culm age in Silesia; this shows certain important deviations from the fructifications previously examined. In the Sphenophyllum strobili from the Coalmeasures the axis bears successive verticils of coherent bracts, the sporangia are borne singly at the end of long pedicils twice as numerous as the bracts, and arising from the upper surface of the coherent disc near the axil. In the Culm species, Sphenophyllum Römeri, sp. nov., the bracts of successive whorls are superposed and not alternate, as described by other writers, in the Coal-measure species; a more important feature of the new form is the occurrence of two sporangia instead of one in each sporangiophore or pedicil. Graf Solms referred to the unique collection of microscopic preparations of fossil plants left by Professor Williamson; he emphasised in the strongest terms the immense importance of the collection, and pointed out how every worker in the field of Palæozoic botany must constantly consult the invaluable type specimens in the Williamson cabinets. 3. The Chief Results of Williamson's Work on the Carboniferous Plants. By Dr. D. H. SCOTT, F.R.S. The origin and history of the late Professor Williamson's researches on the Carboniferous flora were briefly traced. His great work, chiefly, though not entirely, contained in his long series of memoirs in the Philosophical Transactions' of the Royal Society, consisted in thoroughly elucidating the structure of British fossil plants of the coal period, and thus determining, on a sound basis, the main lines of their affinities. Four of the principal types investigated by Williamson were selected for illustration-the Calamarieæ, the Sphenophyllea, the Lyginodendreæ, and the Lycopo diacea. (1) The Calamarie.-Williamson's great aim, which he kept in view all through, was to demonstrate the essential unity of type of the British Calamites, i.e. that they are all Cryptogams, of equisetaceous affinities (though sometimes heterosporous), both possessing precisely the same mode of growth in thickness by means of a cambium, which is now characteristic of Dicotyledons and Gymnosperms. 1 For a fuller account of Dr. Hansen's work, see the Annals of Botany, 1895. His researches have given us a fairly complete knowledge of the organisation of these arborescent Horse-tails. (2) The Sphenophylleæ, & remarkable group of vascular Cryptogams, unrepresented among living plants, but having certain characters in common both with Lycopodiaceae and Equisetacea, are now very thoroughly known, owing, in a great degree, to Williamson's investigations. The discovery of the structure of the fructification, absolutely unique among Cryptogams, was in the first instance entirely his own. (3) The Lyginodendreæ.-The existence of this family, which consists of plants with the foliage of ferns, but with stems and roots which recall those of Cycads, was revealed by Williamson. This appears to be the most striking case of an intermediate group yet found among fossil plants. (4) The Lycopodiacea.-Williamson added enormously to our knowledge of this great family, and proved conclusively that Sigillaria and Lepidodendron are essentially similar in structure, both genera, as well as their allies, being true Lycopodiaceous Cryptogams, but with secondary growth in almost all cases. He demonstrated the relation between the vegetative organs and the fructification in many of these plants, and by his researches on Stigmaria, made known the structure of their subterranean parts. The different types of Lepidodendron, of which he investigated the structure, were so numerous as to place our knowledge of these plants on a broad and secure foundation. The paper was illustrated by lantern-slides, partly from Williamson's figures, and partly original. 4. The Localisation, the Transport, and Rôle of Hydrocyanic Acid in Pangium edule, Reinw. By Dr. T. M. TREUB, Buitenzorg, Java. Five years ago Dr. Greshoff made the remarkable discovery that the poisonous substance contained in great quantities in all the parts of Pangium edule, was nothing else than hydrocyanic acid. This interesting chemical discovery was the starting-point of Dr. Treub's physiological investigations. In microchemical researches hydrocyanic acid presents a great advantage, as compared with the great majority of substances to be detected in tissues by reagents; namely, that the Prussian blue reaction, easily applicable in microchemical research, gives completely trustworthy results. The appearance of Prussian blue in a cell may be accepted as certain proof of the previous occurrence in the cell of hydrocyanic acid, no other substance producing the same reaction. The leaves prove to be the chief factories of hydrocyanic acid in Pangium, though there are other much smaller local factories of this substance in the tissues of other organs. The hydrocyanic acid formed in the leaves is conducted through the leaf-stalks to the stem, and distributed to the spots where plastic material is wanted. The acid travels in the phloem of the fibro-vascular bundles. Dr. Treub regards the hydrocyanic acid in Pangium edule as one of the first plastic materials for building up proteids; he thinks it is, in this plant, the first detectable, and perhaps the first formed product of the assimilation of inorganic nitrogen. In accordance with this hypothesis, the formation of hydrocyanic acid in Pangium depends, on the one hand, on the presence of carbo-hydrates or analogous products of the carbon-assimilation, and, on the other hand, on the presence of nitrates. These two points were proved, or at least rendered probable, by a great number of experiments made by Dr. Treub in the Buitenzorg Gardens. (The details of this investigation will be found in a paper published in the Annales de jardin botanique de Buitenzorg'). 5. Exhibition of Models illustrating Karyokinesis. Professor Farmer described a set of wax models illustrating the typical forms passed through, and the chief variations exhibited by, the chromosomes during the division of the nucleus in the spore-mother cells of plants. The wax employed is made of a mixture of one part of white wax, with five parts of paraffin, the melting point of which is about 50° C. SATURDAY, SEPTEMBER, 14. The Section did not meet. MONDAY, SEPTEMBER 16. A joint discussion with Section B was held on the Relation of Agriculture to Science. See p. 660. 1. On the Destruction of a Cedar Tree at Kew by Lightning. By W. T. THISELTON-DYER, F.R.S. The President of the Section exhibited photographs and specimens of a large cedar (Cedrus Deodara, Loud.) from Kew, which had been struck and completely shattered by lightning on August 10. It was pointed out that the main stem had been in part blown into matchwood by the violence of the shock, and branches were torn off with large portions of the trunk adhering to their base. The explosion seemed to have been centrifugal, the stem having been disrupted from the centre, and not merely stripped superficially. 2. On the Formation of Bacterial Colonies. By Professor MARSHALL WARD, F.R.S. The author has examined the details of development of the colony in numerous species from a single spore by employing microscopic plate-cultures, which can be kept under observation with a one-twelfth and even a one-twentieth oil-immersion lens, or by making pure Klatschpräparate on cover-slips covered with a thin film of gelatine. He finds many factors of importance affecting the form, extent, rapidity of growth, and other characters of colonies; the elasticity of the gelatine, the presence of moist films on the surface of the gelatine, the rate of (slight) liquefaction, &c., all being of importance in explaining the shapes, &c., of submerged colonies-whetstone shaped,' moruloid, spherical, or lobed colonies-the mode of emergence and spreading over the surface of the gelatine, the formation of radiating fringes, iridescent plates, &c. Exposure to light during the development of liquefying colonies may profoundly affect their shape and other properties, a phenomenon closely connected with the retardation of liquefaction and growth. Pigment bacteria may give rise to perfectly colourless races when cultivated under certain conditions, and the colour restored by again changing the conditions; a fact which the author has not only confirmed with red forms, but which he shows to be true of a violet bacillus. Species commonly described as non-motile show active movements under certain conditions, and the sizes of bacteria are not constant in different regions of one and the same colony. Details have been worked out for series of types the extremes of which differ considerably in liquefying power, and essential difference in the appearance of a colony may depend on the amount of liquefying power evinced, |