March 14, 1889] 



NA TURE 



479 



> which is inapplicable the law based on the circular theory — 

 that is, the eijjht-point rule. Instead of the usual barometric 

 piessure in form of a basin, it is stated to have presented the 

 aspect of an immense linear depression, a ti-ough of low barometer 

 i.oving eastwards. This view is incompatible with the well 

 iiown hypothesis advocated by M. Faye, who accordingly 

 codeavcurj here to account for the recorded phenomena without 

 having recourse to the "highly improbable theory of a vast 

 trough of low temperature." — On the complete rectification of 

 the sextant, by M. Gruey. Two methods are proposed, dealing 

 with the rejiifioation of the axis of rotation, R, of the large 

 mirror M, with the rectification of the large and small 

 mirrors M and M', and with that of the axes U and S. — 

 I )n the separation of zinc and cobalt, by M. H. Baubigny. In 

 a pre/ious paper {Comptes rendus, cviii. p. 236) the author de- 

 scribed the process by which he has succeeded in completely 

 separating zinc and nickel. The further experiments here 

 carried out tend to show that, even in the state of sulphates, zinc 

 and cobalt cannot be totally separated by sulphuretted hydrogen 

 in presence of a small exces- of free sulphuric acid unless the 

 quantity of cobalt be relatively slight. The separation may also 

 be effected with sufficient completeness if the quantity of zinc be 

 slight. — Observations on saccharification by diastase, by M. L. 

 Lindet. During saccharification the decomposition of the starch 

 into maltose and dextrines is always accompanied by a secondary 

 reaction in which the diastase attacks the dextrines and trans- 

 forms them to maltose. This reaction is arrested by the pre^^ence 

 of a certain <iuanlity of maltose, which, however, may be re- 

 moved by alcoholic fermentation, as maintained by Payen, 

 although denied by O' Sullivan and others. Here M. Lindet 

 confirms Payen's theory by another process, employing phenyl- 

 hydrazine as a reagent for precipitating the maltose in the state 

 of insoluble phenylmaltosazone. — On some new neutral and acid 

 ethers of the camphols, by M. A. Haller. These ethers are 

 foimed under the same conditions as the succinates already de- 

 scribed in the Comptes rendus of February 25.— Influence of 

 mineral substances on the structure of plants, by M. Henri Jumelle. 

 The experiments here carried out with lupins cultivated under 

 like conditions, but some with distilled water, some with Knop's 

 mineral solution, show that the presence of mineral substances 

 is followed by a greater development of sap, and diminished 

 formation of supporting elements ; further, that the absence of 

 salts considerably modifies the structure of plants, the modifica- 

 tions, however, being largely due less to the absence of the salts 

 (J themselves than to the consequent diminution of water attracted 

 and retained by the salts. — I'apers were contributed by M. E. 

 Goursat, on isogonal transformations in mechanics ; by M. S. 

 Arloing, on the general effects of the substances produced by 

 Hac llus heiiiinecrobiophilus under natural and artificial culture ; 

 by M. Stanislas Meunier, on the Carboniferovis rocks containing 

 Jntcillarites, Stur ; and by M. de Rouville, on the genus 

 Ainphion {Pander) in the Cabrieres district, Herault. 



Berlin. 

 Physijlogical Society, February i. — Prof, du Bois Rey- 

 mond. President, in the chair. — Prof. Moebius spoke on the 

 m.^vements of the flying-fish through the air. He first described, 

 from personal otjservation, the way in which the fish shoot out 

 of the water from both bows of the ship, and then propel them- 

 selves horizontally for a distance of .several ship's-lengths with 

 their pectoral and abdominal fins stretched out flat, skimming 

 along without moving their fins, always in the direction of the 

 wind, but either with or against the same. When they meet the 

 crest of a wave they raise themselves slightly in the air, falling 

 again to the same extent in the succeedmg trough of the sea. 

 Occasionally a slight buzzing of the fins may be observed, similar 

 to that of the movements of the wings in many insects. At night 

 they frequently fall on the deck of the ship. As the result of a 

 detailed investigation, the speaker had proved that these fish do 

 not fly, since the anatomical arrangements of their fins and 

 muscles are not adapted to this purpose. What really occurs is 

 that when frightened by the approach of a ship or any enemy 

 they shoot up out of the water, as do so many other fish, and are 

 then cariied along by the wind, which strikes on the under sur- 

 face of their outstretched and evenly-balanced fins. Notwith- 

 standing the general acceptance which was accorded to the above 

 investigation, it was urged by many that the buzzing of the fins, 

 the rising over the crest of a wave, and the falling overboard 

 after having landed on the deck of a ship, were evidences that 

 t lis fish really executes movements which result io flight. In 



reply to this, the speaker pointed out that the buzzing of the fins 

 takes place when a strong current of air is direct«d against the 

 outspread fins of a dead flying-fish by means of a bellows, and 

 further, that the rising over the crest of a wave or the/bulwarks 

 of a ship may be explained by the ascending currents of ai: 

 which are always produced whenever a strong horizontal wind 

 strikes against any elevated object such as a wave or part of a 

 ship. Thus, finally, with the exception of the movtna:nt> 

 involved in its oblique sudden exit from the sea, all the mo ions 

 of a flying fish when in the air are really passive. — Dr. Posn.r 

 spoke on the conversion of mucous membrane into cuticular 

 tissue. It has long been known that ectodermal tissue can 

 become converted into that which is characteristic of the alimen- 

 tary tract ; thus, for instance, when pieces of skin are trans- 

 planted into the cavity of the mouth, they become co apletely 

 converted into mucous membrane, and the epidermis becomes 

 an epithelium. On the other hand, no observations existed as to 

 whether the reverse conveision of mucous into epidermal tissue 

 is possible. No conclusive evidence could be drawn from the 

 cuticular conversions which occur in mucous membranes which 

 are derived from ingrowths of the ectoderm, and equally incon- 

 clusive were the cases of cuticular conversion which are observed 

 in strictures of the urethra, and in the bladder, and in cases of 

 papilloma and pachydermia of the mucous membrane of the 

 mouth, larynx, and oesophagus. The speaker had found in 

 Leidig a hint that in those animals which do not chew their food 

 a conversion of the gastric mucous membrane occurs, which 

 often amounts to a real cuticular formation. It is true that in 

 birds the gizzard is possessed of tubular glands which pour out a 

 secretion which at once sets into a mass as hard as bone, and 

 provides a means of comminuting the food. But, on the other 

 hand, cuticular growths are observed in the stomachs of Eden- 

 tata, which consist of a true conversion of epithelium into 

 epidermis. The speaker had been able to study this conversion 

 I in the stomach of Manis, and found by chemical and micro- 

 I scopical investigation that the whole stomach, even down to the 

 j region of the pylorus, is lined with a true epidermis, and that 

 \ typical papilUe are developed unierneath the same. The con- 

 ' version of endodermal into ectodermal structures is hereby 

 I clearly proved, a fact which is not devoid of significance itv 

 : pathology. 



February 15. — Prof, du Bois Reymond, President, in the 

 I chair. — Prof. F. E. Schulze spoke on the organization and 

 I mode of living of Sponges. The simplest form of Spon{,e 

 consists of a sac, which, being composed of three layers, 

 I is equivalent to the embryonic form of the more compli- 

 j cated types. This sac is attached by its base, and has at its^ 

 \ apex an opening — the osculum ; its wall is composed of an 

 j outer layer of epithelial cells (ectoderm), a midd e layer of con- 

 nective-tissue with migratory cells (mesoderm), and an inner 

 layer of collared flagellated cells (endoderm), and is perforated 

 with round and regularly distributed apertures. The more com- 

 plex forms arise by a thickening and folding of the wall, the 

 thickening being still more marked in the most complicated 

 forms. In these, a system of branched canals takes the place of 

 the simple apertures in the wall, communicating with the exte- 

 rior by round openings, and leading internally into cavities lined 

 with collared flagellated cells (choanocytes) ; from these cavities 

 a further system of branched canals leads into the now limited 

 internal cavity with its osculum. The skeleton of the Sponge is 

 composed of chalk, siliceous earth, spongin, or foreign sub- 

 stances. In the simplest Sponges, consisting of a simple sac, 

 the skeleton is made up of the simplest star-shaped spicules, 

 with three rays, so as to give support to a membrane which is 

 perforated with regularly alternating apertures ; in the more 

 complicated forms, these spicules possess four or six rays, a* 

 supplying the most convenient supporting stiucture, while a 

 collar of simple rays is developed round the osculum. Accord- 

 ing to the material of which the skeleton is chiefly composed. 

 Sponges may be classified as ch.ilky, siliceous, horny, or sandy. 

 The Ilexactinellidae, with six-rayed spicules, inhabit deep seas. 

 In all Sponges, a continuous stream of water is observed entering 

 the openings on the surface of the body, and emerging at the 

 osculum, so that the Sponges filter the water in which they live. 

 The movement of the water is brought about by the flagella ; 

 the contraction and retraction of the osculum is produced by 

 elongated protoplasmic cells, but these cannot be regarded as 

 muscle-cells until it has been proved to a certainty that they are 

 connected with nerves, atid receive their imi)ulse from these 

 nerves. Only one observer has as yet described a nervous system. 



