March 24, 1898] 



NATURE 



501 



charge was tried, but found for various reasons to be less suit- 

 able for the comparison immediately in view than that adopted. 

 It is, however, the only method by which, for several of the 

 specimens, results at ordinary temperatures can be obtained. 

 Special care was taken to ensure that no disturbing film of 

 moisture existed on the surface of the glass, and that the con- 

 duction was entirely through the plate or the walls of the flask 

 experimented on. 



The specific inductive capacities were determined by connect- 

 ing the condenser formed by the specimen, for about 1/30,000 

 of a second, with one of Lord Kelvin's air leydens, which had 

 been previously charged, and observing the potential of the 

 leyden before and after the contact. 



After the electrical determinations had been made the speci- 

 mens were very carefully analysed, and the results are given 

 in the paper, which contains, therefore, full information as to 

 the precise composition of the glasses. 



The anticipation mentioned above was fully borne out. The 

 specific resistance of the lead potash glasses was for one cer- 

 tainly above 18,000 x 10^" ohms at 100° C. , for another above 

 35,000 X 10'* ohms at all temperatures up to 135° C. The 

 specific resistance of the barium glass was also very high ; and, 

 what was remarkable in this glass, there was hardly any trace 

 of dielectric polarisation. The authors are pursuing experiments 

 on the electrical and mechanical properties of this glass. 



It was found, after the communication of the paper, that the 

 almost complete replacement of the potash in a lead glass by 

 soda diminishes the specific resistance. 



The research is being continued with a view to settling a large 

 number of interesting points which have arisen in the course of 

 the work. For this purpose special glasses of as nearly as 

 possible prescribed composition are being made by Messrs. 

 Powell and Sons. 



March 3. — " On Apogamy and the Development of Sporangia 

 upon Fern Prothalli." By William H. Lang, M.B., B.Sc. 



In this paper the results obtained from a series of cultures of 

 ten species of ferns, the prothalli of which were grown for more 

 than two years, are described. The conditions of cultivation 

 differed from those under which prothalli usually occur in nature, 

 in that fertilisation was prevented by avoiding watering irom 

 above ; the prothalli were also exposed to direct sunlight. To 

 these causes the results, which in the main agree for the various 

 species, may be ascribed. The most important were the change 

 in form and structure of the prolhallus to a fleshy cylindrical 

 process, which sometimes proceeded from the apical region, 

 sometimes from the . under surface just behind the latter ; the 

 development of conical projections around or in place of 

 archegonia, and the occurrence of more or less numerous cases 

 of apogamy in every one of the species. The latter phenomenon 

 was manifested by the presence of tracheides in the tissue of the 

 prothallus, by the development of isolated members of the 

 sporophyte upon it, and, in every case but one, of complete 

 vegetative buds. On prothalli of Scolopendritcm vulgare and 

 Nephrodium dilatatutii sporangia, which sometimes attained 

 almost perfect development, were found. In conclusion the 

 bearing of the results on the nature of the alternation of genera- 

 tions seen in archegoniate plants is considered, and a provisional 

 hypothesis is suggested to explain how the definite alternation of 

 sexual and asexual forms might have originated by modification 

 of individuals of the ancestral algal organisms under the con- 

 ditions to which they would presumably have been exposed on 

 their assumption of a terrestial mode of life. 



"Experimental Observations on the early Degenerative 

 Changes in the Sensory End Organs of Muscles." By F. E. 

 Batten, M.D. Communicated by Prof. Victor Horsley, F. R.S. 



The experiments described in the following paper were 

 undertaken in order to show, firstly, that degeneration occurred 

 in the first place in that part of the neuron most remote from 

 the cell, and secondly, to reproduce within the muscle-spindle, 

 if possible, certain changes which had been shown by the 

 author to be present in the case of tabes dorsalis in man. 



The results of the research have been to show : 



( 1 ) That within the muscle-spindle a spiral form of nerve ter- 

 mination exists surrounding a fine muscular fibre, in the centre 

 of which are large, clear, non-nucleated cells. 



(2) That changes take place in the spiral in twenty-four hours 

 after section of the nerve, and that such changes become 

 marked in forty-eight hours. 



(3) That degeneration of the medullated sheath of the nerve 



NO. 1482, VOL. 57] 



takes place in the whole course of the nerve at the same time 

 after section of the nerve. 



(4) That no fatty change could be demonstrated in the intra- 

 muscular cells by the Marchi method similar to those found in 

 the case of tabes dorsalis in man. 



Entomological Society, March 2. — Mr. G. H. Verrall, 

 Vice-President, in the chair. — Lord Walsingham exhibited a 

 series of the larger and more striking species of Xyloryctinje, a 

 subfamily of the Gelechiidce, especially characteristic of the 

 Australian fauna. The series illustrated the life-histories and 

 the great disparity in colour and form between the sexes of many 

 species. He also gave an account of the family, chiefly from 

 notes by Mr. Dodd (of Queensland), with especial reference to 

 the habits of the larvae, which live in holes in tree-trunks, to 

 which they drag leaves in the night for the next day's consump- 

 tion. — Mr. Gahan exhibited a locust, Acryditim ffgyftium 

 (= tartaricuin), taken in a house in Hanover Square, and 

 probably imported in vegetables. — Mr. Kirkaldy exhibited 

 species of water-bugs, including Enicocephahis ailicis and 

 Gerris robust us, both taken for the first time in Mexico. — A 

 discussion arose on the reported occurrence of the San Jose 

 scale, Aspidiotus perniciosus, in Great Britain. 



Linnean Society, March 3. — Dr. St. George Mivart, 

 F. R.S., Vice-President, in the chair. — Mr. Thomas Christy 

 exhibited specimens of the Mora Nut of British Guiana 

 (Dtntorphandra Mora, Schomb. ), of which some had been 

 lately introduced into London by Colonial brokers as the 

 Kola Nut {Cola acuminata). It appeared, however, on 

 analysis, that the former contains no caffeine, a product for 

 which the latter is of definite commercial value. It remained 

 to be ascertained whether the Mora Nut has any economic 

 value. — Prof. W. A. Herdman, F.R.S., read a paper by Mr. 

 F. J. Cole, entitled "Observations on the structure and Mor- 

 phology of the cranial nerves and lateral sense organs of 

 fishes, with especial reference to the genus Gadtts'' It con- 

 tains the first description of the lateral-line organs of Gadiis, 

 and pit-organs were shown to be present. The author concludes 

 that the lateral-line system of fishes was not originally metameric, 

 and that it has nothing to do with the branchial sense-organs. 

 He regards it and the auditory organ as parts of a system, and 

 their nerves (viz. the superficial ophthalmic, buccal, external 

 mandibular, lateralis, and lateral-line nerves), together with the 

 auditory, as of a series sui generis, and shows that the so called 

 lateral-line nerve of Petromyzo7i really belongs to the lateralis 

 accessorius system (ramus lateralis trigemini, auct. ), the mor- 

 phology of which he fully describes. The paper deals ex- 

 haustively both with the afore-mentioned and the subsidiary 

 branches of the subject, which is treated in detail and histori- 

 cally, with an accompanying exhaustive bibliography. — Prof. 

 Howes, discussing the paper at some length, drew attention to 

 some observations of the Cousins Sarasin, and to the experi- 

 mental work of Sewall, Steiner, Lee and others upon the 

 auditory apparatus of fishes, which he believed lent support to 

 the author's conclusions. — Mr. G. Claridgc Druce read a paper 

 on the occurrence of Carex helvola, Blytt, in Britain, in which 

 he gave an account of his discovery of this plant on Bin Lawers, 

 Perthshire, in August 1897. He found, it growing in some 

 abundance at an elevation of about 3200 feet. Prof. Blytt and 

 Dr. Christ, to whom specimens had been submitted, both agreed 

 in naming it C. helvola, which by many botanists is considered 

 to be a hybrid. — A report by the Rev. O. P. Cambridge, 

 F. R.S., upon the spiders collected by Mr. Fisher, of the 

 Jackson-Harmsworth Polar Expedition, was read by Mr. 

 A. D. Michael. They consisted of three species, all be- 

 longing to the genus Erigone, one of which had been previously 

 described, though not figured by Thorell ; and another was 

 new, but closely allied : the author proposes to call the latter 

 E. Fisheri. 



Geological Society, March 9. — W. Whitaker, F. R.S. 

 President, in the chair. — Prof. J. W. Judd exhibited, on behal 

 of the Coral Reef Committee of the Royal Society, the lowest core 

 (698 feet) from the boring at Funafuti (Ellice Island), and drew 

 attention to the remarkable changes exhibited by the rocks ob- 

 tained at this depth. The core from this boring (a mass of 

 material more than a ton in weight) had been sent to thiscouotiy 

 by Prof. Edgeworth David, and was now being submitted to 

 careful study. The last 20 or 30 feet of the boring was carried 

 on in a rock which was of a very soft character, and highly but 

 minutely crystalline. Microscopic examination shows that the 



