ii8 



NA TURE 



[May 30, 1907 



uncertainty as to whether the barium sulphide is not con- 

 verted into oxide by water-vapour in the flame. 



The explanation given by Lenard, of the flame color- 

 ation by the alkali salts, appears to be inapplicable to 

 the coloration of the carbon monoxide flame by the haloid 

 salts of the alkaline earth metals. 



February 21. — " Longitudinal Symmetry in Phanero- 

 gamia." By Percy Groom. Communicated by Dr. D. H. 

 Scott, F.R.S. 



The paper describes a graphic method of recording the 

 longitudinal distances apart of plant members, and gives 

 results obtained by the method, which is as follows : — 



On squared paper the successive internodes (or other 

 segments) are recorded as successive ordinates, and the 

 resultant curve is termed the internode curve (or other 

 curve). 



In a typical herb the internode curve of the main axis 

 is a regular ascending-descending one, while those of the 

 successive branches commencing at the base of the herb 

 more or less completely and gradually change from this 

 complete curve to a purely descending one. These inter- 

 node curves are shown to be inherent, though liable to 

 modification by external conditions. 



In alternate-leaved Chenopodiacese the internode curve 

 invariably shows a periodic zigzag form, and, by connect- 

 ing the alternate ordinates, can be analysed into two " sub- 

 curves " which are frequently not synchronous in period. 

 Both these subcurves of the main axis are of the 

 ascending-descending type, while those of the successive 

 branches traced from below more or less change into the 

 purely descending form. Of the two subcurves, one is 

 the " internode subcurve " and the other is the " displace- 

 ment subcurve." Evidence is given in favour of the view 

 that the original phyllotaxis of the Chenopodiaceas was 

 opposite, that the internode subcurve represents a modifi- 

 cation of the original internode curve, and that the dis- 

 placement subcurve represents a series of intercalated 

 segments registering the distances up which single leaves 

 have been displaced from the original opposite arrange- 

 ment. 



This view is confirmed by the fact that a similar dis- 

 placement curve is formed by recording the heights of the 

 successive branches above their subtending leaves in certain 

 BoraginaceEe. It is shown, too, that the Boraginaceae are 

 probably opposite leaved in design, and that in SoXanuin 

 Dulcamara the familiar leaf displacements high up the 

 stem are foreshadowed by others lower down. 



One point of significance in connection with these 

 assumed hereditary displacements is that they follow the 

 rule formulated by de Vries in reference to the dimensions 

 and distribution of monstrosities. 



The paper also discusses smaller or more fluctuating 

 displacements of leaves ; double-leaves ; the correlation of 

 alternate rather than successive internodes and nodes where 

 phyllotaxis is cyclic ; and the theory of stem structure. 



Finally, the applicability of the method to other morpho- 

 logical problems is tested by observations on sympodes, 

 with a positive result in the case of Ampelopsis hederacea. 



March 14. — " Capillary Electrometer Records of the 

 Electrical Changes during the Natural Beat of the Frog's 

 Heart." By Prof. Francis Gotch, F.R.S. 



The «hief points brought forward in this communication 

 are the following : — (i) The electrical changes during the 

 natural rhythmic activity of the frog's heart, when kept 

 in situ and supplied with blood, resemble in all essentials 

 those observed by Waller, Starling, Bayliss, Einthoven, 

 &c., in the mammalian heart, but do not correspond with 

 those observed by Engelmann, Burdon-Sanderson, &c., in 

 the excised frog's heart artificially excited. (2) The more 

 prolonged character of the activity of the frog's heart, and 

 the ease with which the locality of any change can be 

 determined, render it clear that the special feature of the 

 natural beat is the occurrence of two chief electrical 

 changes of similar sign. (3) This is explicable as due to 

 the first or base change being more prolonged and of 

 greater magnitude than the apex change. (4) The in- 

 creased duration and magnitude of the base change is 

 mainly caused by the circumstance that, although the base 

 change occurs first, the whole of the base is not involved, 

 the portion around the spring of the aorta remaining 



NO 1 96 I, VOI-. 76] 



quiescent until the activity has occurred at the apex ; this 

 aortic portion then becoming active produces the terminal 

 effect. (5) Each contraction wave thus starting at the 

 auriculo-ventricular junction is propagated to the apex, and 

 returns from the apex to the part of the base around the 

 start of the aorta ; from this it spreads to the aortic bulb ; 

 at 15° C. the propagation rate is about 130 mm. in one 

 second, i.e. 6/100" after the first base change, an apex 

 change is perceptible, and 6/100" after the apex, a second 

 aortic base change. (6) The return wave is brought into 

 prominence when the heart is distended with blood, or has 

 been so distended, and is associated with the persistence 

 of the early tubular condition which prevails in the heart 

 of the tadpole. (7) The return wave reveals itself in the 

 records as a double reversal of the electromotive condition 

 of the whole base contact ; this is at first galvanometrically 

 negative (base activity), then suddenly positive (apex 

 activity), and then, again, suddenly negative (second 

 aortic part of base activity). It is confirmed by records 

 made under a variety of conditions, comprising local alter- 

 ations of temperature, local injury, and altered position of 

 electrometer contacts. AH the records were those of the 

 displacements of the capillary meniscus, photographed 

 upon moving sensitised plates. 



Entomological Society, May i. — Mr. C. O. Waterhouse, 

 president, in the chair. — Exhibits. — Coleoptera from Ice- 

 land : Mr. O. E. Janson exhibited a small collection of 

 Coleoptera made by him in Iceland in July, 1906, com- 

 prising thirty-nine species, of which some were previously 

 unrecorded as inhabiting that island. He also directed 

 attention to the affinity between the beetle fauna of 

 Iceland and of Scotland, only one of those taken, 

 Colymbetes groenlandicus, Aub^, not occurring in both 

 countries. — Larvae of Otiorrhynchus suhatus : Mr. J. A. 

 Clark brought for exhibition living larvae of Otiorrhynchus 

 sulcatus feeding on the roots of ferns. — Coleoptera from 

 the south of trance : Commander J. J. Walker showed 

 living specimens of Oxythyrea stictica, L., Epicometis 

 hirtella, L., and Anthaxia parallela, taken by Dr. T. A. 

 Chapman at St. Maxime, Var, S. France. — Mimetic re- 

 lation of Leuceronia argia, 9 • Dr. F. A. Dixey exhibited 

 specimens of seven different forms of the variable female 

 of Leuceronia argia, Fabr., showing that each form stood 

 in mimetic relation with a separate model. The models 

 belonged to the genera Belenois, Phrissura, Pinacopteryx, 

 and Mylothris, and the association was probably in every 

 instance synaposematic. — Mimicry in Coleoptera ; the 

 President exhibited some Coleoptera collected in Pahang 

 by Mr. H. C. Robinson, and recently received at the 

 Natural History Museum. — Living luminous Coleoptera : 

 Dr. G. B. Longstaff exhibited living specimens of the 

 Elaterid Pyrophorus noctilucus, Linn., brought from 

 Trinidad by Dr. F. L. J. M. de Verteuil, K.ti.—Quedius 

 riparius and Trypodcndron quercus : Mr. H. St. J. 

 Donisthorpe exhibited on behalf of Prof. T. Hudson 

 Beare and himself specimens of Ouedius riparius, Kell., 

 and Trypodcndron quercus, Eich., taken by them at Por- 

 lock, Somersetshire, on April 16 and 17. Also Hydrovatus 

 clypealis, Shp., taken by them on April 14 at Worle, near 

 Weston-super-Mare. — Dipteron associated with ants : Mr. 

 Donisthorpe also showed the larva and pupa of a 

 Dipteron of the genus Microdon, taken in a nest of 

 Formica fusca at Porlock last month. — Hcmimerus 

 talpoides, Walk. : Mr. R. Shelford exhibited a specimen 

 of the curious parasitic orthopterous insect Hemiinerus 

 talpoides, Walk., from Portuguese Guinea. — Paper. — .\ case 

 of homceotic variation in a cockroach : R. Shelford. 



Linnean Society, May 2. — Prof. W. A. Herdnian, F.R.S., 

 president, in the chair. — The respiratory mechanism in 

 certain elasmobranchs : A. D. Darbishire. The author 

 exhibited living examples of the dog-fish, ray, and angel- 

 fish, and explained that the primary object of the investi- 

 gation was to determine the question whether water went 

 in, or was expelled, from the spiracle of the dog-fish. The 

 method employed to elucidate this point consisted in 

 liberating from a pipette some powdered carmine suspended 

 in sea-water in the immediate vicinity of the spiracle. The 

 cloud of carmine was seen to be vigorously drawn in at 

 each inspiring phase. A remarkable difference was dis- 

 covered to exist between the respiratory mechanism in the 



