PROCEEDINGS OF THE SOCIETY. 643 



AN ORDINARY MEETING 



OF THE Society was held at No. 20 Hanover Square, W., 

 ON Wednesday, November 21st, 1917, Mr. J. E. Barnard, 

 Vice-President, in the Chair. 



The Minutes, having been duly circulated, were taken as read, con- 

 firmed, and signed by the Chairman. 



The Chairman invited Fellows to nominate candidates for election 

 to the Council by sending names, each supported by three sponsors, to 

 the Secretary as soon as possible. 



Mr. Scourfield exhibited the protonema of the so-called " luminous 

 moss," Schisiostega. It was not a common moss, although it had been 

 recorded from several parts of England, occurring in such situations 

 as disused mine adits, entrances to caves, and even in rabbit-burrows. 

 He was shown this moss for the first time this year by Mr. G. T. Harris, 

 of Sidmouth, in rabbit-burrows on Dartmoor. When seen, it was a 

 most striking object. The moss, or rather its protonema, appeared to 

 glow with a metallic golden-green light, producing an effect similar to 

 that obtained from some tropical butterflies, or from certain humming- 

 birds. This was not due to phosphorescence, but to reflection of light 

 by certain special cells, the reflected light being no doubt modified by 

 the presence of chlorophyll. A specimen, growing on a stone, was under 

 one of the microscopes, illuminated by a vertical illuminator, and showed, 

 to some extent, how the light was reflected. In ordinary mosses the pro- 

 tonema was composed of a series of threads, resembling a filamentous alga ; 

 but in Schisiostega the threads at certain points developed into special 

 cells, with eight to sixteen chlorophyll grains arranged as a rule at the 

 bottom of each cell. The cells were nearly spherical, but seen edge-on 

 produced the paraboloid effect shown in the drawing on the black- 

 board of a figure from Stras burger's " Text-Book of Botany." It had 

 been suggested that incident light, after entering the cell, was re- 

 flected from the sloping sides, across the cell, and out again. 



The Chairman remarked that mere reflection was hardly sufficient to 

 account for the emission of light which had a dominant wave-length, 

 so that green coloration w'as produced. 



Mr. Scourfield believed that the greenish colour was due to the 

 chlorophyll. 



The Chairman, continuing, said in this case it was probably due to 

 a change in the wave-length of the light entering the moss, due to 

 absorption of part of the light, rather than to simple reflection, and was 

 somewhat parallel to the emission of light by luminous bacteria. There 

 the light was of one wave-length, and it constituted a wonderful example 



