April 14, 1 881] 



NA TURE 



563 



lings of various species of Pinus which have grown in the 

 dark, inasmuch as it has long been known that these 

 plants become green in darkness. 



This paper cannot be regarded as other than a most 

 important contribution to our knowledge of the physio- 

 logy of plants, and it will be readily admitted that Prof. 

 Pringsheim's theory of the function of chlorophyll is at 

 least as satisfactory as any which are now current. But 

 although the number of facts upon which the theory is 

 based is large, yet the evidence in favour of it can hardly 

 be considered to be complete at present ; there are 

 certain points whicii require further elucidation. For 

 instance, Prof. Pringsheim regards the chlorophyll of a 

 corpuscle as undergoing no change under ordinary circum- 

 stances, but it is difficult to reconcile this view with the 

 fact that an alcoholic solution of chlorophyll loses its 

 colour under the same circumstances. Then again, as 

 to the source of the reducing energy in the process of 

 assimilation, if the rays absorbed by the chlorophjU are 

 not directly concerned in it, it is most desirable that more 

 information should be obtained as to the nature of the 

 rays which are active, and as to the particular cell-contents 

 whicli absorb them. Further, the correctness of the 

 principle that an increase in the intensity of light to 

 which a cell is^exposed produces an increase of its respi- 

 ratory activity, needs more direct and general experimental 

 confirmation than is given here. In his views as to the 

 respiratory function, he appears to insist too strongly that 

 the chlorophyll-corpuscles are to be regarded not only as 

 assimilatory, but also as respiratory organs. It is not 

 easy to see that any of the observations which he .gives 

 in this paper directly suggest such a view; on the con- 

 trary, they tend rather to show that exposure to intense 

 light increases oxidation in the lu/w/e of the protoplasmic 

 cell-contents. Prof. Pringsheim evidently desires to bring 

 out that hypochlorin is the substance which undergoes 

 oxidation in the cell, and since it is present exclusively 

 or nearly exclusively in the chlorophyll-corpuscles, he 

 considers that these bodies are the especial seats of the 

 respiratory process. His observations, however, do not 

 warrant this conclusion ; what they prove is that the 

 hypochlorin in the chlorophyll-corpuscles is oxidised when 

 they are exposed to intense light in an atmosphere con- 

 taining oxygen, and that certain changes (including a loss 

 of substance) take place in the rest of the protoplasm, in 

 consequence, doubtless, of the excessive oxidation of some 

 substance or substances which it contains. His view 

 may be fairly met with the a priori objection that it is 

 highly improbable that the same organ should be the seat 

 of two such opposite functions as respiration and assimi- 

 lation. The true physiological significance of the chloro- 

 phyll-corpuscles becomes apparent when it is borne in 

 mind that assimilation does not take place in cells which 

 do not possess them, whereas respiration proceeds actively, 

 perhaps most actively, in such cells. 



.And, finally, as to hypochlorin, it is to be hoped that a 

 method will be devised for the extraction of this substance 

 in such quantities as to allow its properties to be studied 

 and its chemical composition to be ascertained. The 

 curious fact that hypochlorin cannot be detected in plants 

 which are not distinctly green (Diatomacea;, Fucacese, 

 &c.), is worthy of further investigation. 



These desiderata may perhaps be supplied in the future 

 publications on this subject which Prof. Pringsheim 

 promises. Sydney H. Vines 



NOTES 

 We take the follou ing from the Times: — At iheir meeting 

 last week the President and Council of the Royal Society selected, 

 from the whole number of fifty-two candidates for the fellowship, 

 the following fifteen to be recommended to the Society for election 

 at the ani.ual meeting on June 2 ne.tt : — W. E. Ayrton, H. W. 

 Bate?, J. S. Bristowe, W. H. M. Christie, G. Dickie, A. B. 



Kempe, A. Macalister, H. McLeod, J. A. Phillips, W. H. 

 Preece, B. Samuelson, M.P., B. B. Stoney, R. H. Traquair, 

 Rev. H. W. Watson, C. R. A. Wright. 



A conversazione of the Society of Telegraph Engineers was 

 held in honour of Prof. Helmholtz in the rooms of Univer- 

 sity College on Monday night. Among those who were present to 

 meet the guest of the evening were many eminent English men 

 of science. Many of the members of the Society and other 

 had lent instruments and apparatus showing .some of the pur- 

 poses to which electricity has recently been appUed, and also the 

 means by which electrical research is still being carried on. 

 On entering the College grounds the visitors saw a very 

 pretty e.ffect caused by one of Mr. Crompton's electric 

 light.=, which had been placed on the top of the portico. 

 The reception-room itself was lit up with little iucandesce15t 

 electric lamps on Mr. Swan's principle. They were arranged 

 in buni;hes of three or four in ground glass globes iUfper.ded 

 from the ceiling, and in fact at first sight they looked like 

 very brilliant gas-burners, no wires being visible. On each 

 side and down the centre of the room were placed tables on 

 which were arrayed all the ne« est inventions in electrical science. 

 On one it was demonstrated how perfectly easy it w as to manage 

 Mr. Swan's lamps ; taking one lamp out of the stand and 

 putting in a new one occupying only a few second?, there being 

 no binding-screws or switches to attend to. Perhaps the most 

 interesting experiment of the evening was the transmission of 

 pictures of natural objects by telegraph, the picture of a butter- 

 fly being most beautifully transmitted by means of a selenium 

 plate. This was shown by Mr. Shelford Bidwell's telephoto- 

 graphic machine. .Mr. Latimer Clark exhibited some rare books 

 on electricity and magnetism, autographs and portraits of emi- 

 nent electricians ; also a poition of the original telegraph line 

 which was laid by the late Sir Frances Ronalds in 1S16, with 

 the original model of Ronalds' telegraph, the original type cast 

 for the Morse telegraph, with autograph of Prof. Morse, and 

 a portion of line laid by W. F. Cooke in 1S37. Mr. Cotterell 

 of the Royal Institution exhibited a very delicate mercury elec- 

 trometer on Lippman's principle, belonging to Prof. Dewar ; 

 and Mr. Robert Sabine performed some pretty experiments 

 illustrating the cause of the motion of the mercury. Mr. Stroh 

 showed the beautiful aj paratus made by him to illustrate Prof. 

 Helmholtz's vowel theory, and Mr. Preece performed several 

 experiments in explanation of the remarkable sounds pro- 

 duced by intermittent light on solid, liquid, and gaseous 

 matter. Mr. George Lund, of the firm of Messrs. Lund 

 and Bleckley, exhibited some synchronous clocks for the Lon- 

 don, Chatham, and Dover Railway Company for coupling 

 up two ordinary telegraph lines at 10 a.m., in order to 

 send the time current. They also applied to the clock a 

 novel automatic arrangement of their own invention, by which, 

 at two minutts to 10 a.m. daily, the current will ring a warning 

 bell, couple up and block against false currents two ordinary 

 telegraph wires, then at 10 a.m. the clock sends the time- 

 current of two seconds' duration, giving time to the clocks in 

 circuit. Immediately upoa the termination of the two seconds' 

 current the lines will be automatically re-established as distinct 

 lines for their ordinary telegraph purposes. All present were 

 pleased to have the opportunity of inspecting Prof. Kennedy's 

 engineering laboratory, where the machine for testing the strength 

 of materials up to fifty tons v^ as seen in operation, and various 

 pieces of brass and copper were tested. The machine-tools 

 were in operation, and a steam-engine of peculiar construction 

 driving them. We look forward with interest to the scientific 

 results we may expect to be brought to light with the testing- 

 machine. The President (Prof. Carey Foster) showed some 

 interesting electrical in=tiuments ; Mr. Richard Anderson a 

 portable galvanometer for testing lightning-conductors ; Profes- 



