i8o 



NATURE 



[May I, 19 19 



— F. Morvillez : The leaf-conducting apparatus of .,t,he 

 Leguminosae.^ — R. Souiges : The embrypgeny of th^ 

 Porvgonaceas. The development of the embrvo in 

 polygonum persicaria. — F. Vies : The transmission of 

 light through emulsions of bacteria and blood cor- 

 puscles. — MM. Lambert, Vies, and de Watteville : An 

 opacimeter for use in bacterial estimations. This 

 consists of a photometer of two circuits starting from 

 the same source of light, one traversing the emulsion, 

 the other submitted to a system permitting a varia- 

 tion of the intensity according to a known law. A 

 diagram of the apparatus is given, together with a 

 detailo<l account of the mode of standardising. — C. 

 Nicolle and C. Lebailly : Hidden experimental infec- 

 tions. Examples drawn from the study of exanthe- 

 matic typhus. Examples are given of the inoculation 

 of rats and guinea-pigs with typhus in which there 

 was no sign of the reality of the infection except the 

 transmission of the disease by the blood to another 

 animal. This is a different type from latent infection, 

 as here the disease evolves in the experimental animal 

 with its periods of incubation, infectious state 

 (septicaemia and virulence), and cure, with no sign 

 that can be noted by the observer. The name infec- 

 tions inapparentes is proposed for this class. There 

 seems no reason to suppose that such facts are ap- 

 plicable to typhus only. — E. P. Cesari : The matura- 

 tion of the sausage. The ripening and flavour of 

 sausages are due to the action of veasts, three new 

 species of which have been isolated. 



BOOKS RECEIVED. 



From Nebula to Nebula ; or, The Dynamics of the 

 Heavens. By <i. H. Lepper. Fourth edition. 

 Pp. 401. (Pittsburgh, Pa. : G. H. Lepper.) 



Lowson's Text-book of Botany (Indian Edition). 

 Revised and Adapted by Bubal Sahni and M. Willis. 

 New and revised edition. Pp. xii + 610. (London: 

 W. B. Clive.) 85. 6d. 



A Contribution to the Physiology of the Fresh-water 

 Sponges (Spongillidas). By H. van Trigt. Pp. vi+ 

 220+vi plates. (Leiden : E. J. Brill.) 



The Fundamental Equations of Dynamics and its 

 Main Co-ordinate Systems Vectoriaily Treated and 

 Illustrated from Rigid Dynamics. By F. Slate. Pp. 

 IX + 233. (Berkeley : University of California Press.) 



Worlds not Realised. iBv W. J. Jupp. Pp. 94. 

 (London : Headley Bros. Publishers, Ltd.) 25. 6d. 

 net. 



Beverages and their Adulteration, Origin, Composi- 

 tion, Manufacture, Natural, Artificial, Fermented, Dis- 

 tilled, Alkaloidal, and Fruit Juices. By Dr. H. W. 

 Wiley. Pp. XV4-421 + 11 plates. (London: J. and A. 

 Churchill.) 21s. net. 



DIARY OF SOCIETIES. 



THURSDAY, May i. 



RovAL Institution, at 3. — Dr. H. S. Hele Shaw: Clutches. 



LiNNEAN Society, at 5. — J. Small : The Pappus in the Compositae. — 

 Montagu Drummond : Notes on the Botany of the Palestine Campaign : 

 I. The Flora of a Small Area in Palestine. — H. N. Dixon : Mosses from 

 Deception Island. 



Institution of Electrical Engineers, at 6. — Dr. C. Chree : Magnetic 

 Storms. 



Chemical Society, at 8.— Prof. J. H.. Jeans : The Quantum Theory and 

 New Theories of Atomic Structure. 



FRIDAY, May 2. 



Royal Institution, at 5.30. — Prof. J. W. Nicholson : Energy Distribu- 

 tion in Spectra. 



Institution of Mechanical Engineers, at 6. — Dr. W. H. Hatfield: 

 ^ he Mechanical Properties of Steel, with Some Consideration of the 

 Question of Brittleness. 



SATURDAY, May ■^. 



Royal Institution, at 3.— Prof H. S. Foxwell : Chapters in the Psycho- 

 logy of Industry. 



MONDA V, May 5. 



Society of Engineers, at 5.— C. O. Bannister : Heat Treatment of S'eel. 



Aristotelian Society, at 8. — Prof J. B. Baillie : The Stereoscopic 

 Cbaracter of Knowledge. 



TUESDAY, May 6. 



Royal Institution, at 3.— Prof. A. KeitH : British Ethnology— The People 

 of Wales and Ireland. , ; 



Institution of Civil Engineers, at 5.30. — Further Discussions : G. 

 Hughes: The Electrical and Mechanical Equipment of the All-Metal 

 Cars of the Manchester- Bury Section, Lancashire and Yorkshire Railway. 

 — F. E. Gob^y : All-Metal Passenger Cars for British Railway. 



RoNTGEN Society, at 8 (at Royal Society of Medicine, i Wimpole Street, 

 W.i).— Prof. W. M. Bayliss: Silvanus Thompson Memorial Lecture— The 

 Electrical Changes in Active Tissues. 



WEDNESDAY, May 7. 



Royal Society of Arts, at 4.30. — J. S. Highfield : The Supply of Elec- 

 tricity. 



Geological Society, at 5.30. — Major Reginald W. Brock: Observations 

 on the Geology of Palestine. 



British Psychological Society (Educational Section), at 6. — Prof C. 

 Spearman : Mental Tests for Vocational Guidance. 

 THURSDAY, May 8. 



Institution of Electrical ENGiNEERs(Joint Meeting with the Iron and 

 Steel Institute), at 2.30. — T. Bibby : Developments in Iron and Steel 

 Electric Furnaces.— W. H. Booth : The Booth-Hall Electric Furnace.— 

 H. A. Greaves ; Application of Electrical Energy to the Melting of Metals. 

 — R. G. Mercer : Electric Furnaces in the Urated Kingdom, 1918. — Axel 

 Sahlin : A New Type of Electric Furnace.— Victor Stobie : Large Electric 

 Steel Melting Furnaces. 



Royal Institution, at 3. — Dr. H. S. Hele-Shaw: Clutches. 



Institution of Mining and Metallurgy, at 5.30. — Annual General 

 Meeting. — Hugh K. Picard : Presidential Address. — H. Standish Ball : 

 The Work of the Miner on the Western Front, 1915-18. 



Optical Society, at 7.30.— Prof F. J. Cheshire: Presidential Address- 

 Polarised Light.— J. Rlieinberg : Graticules. 



lAV 9. 



FRIDAY, 



Royal Astronomical Society, at 5 



R 07 AL I nstitution, at 5. 30. — Sir George Macartney : Chinese Turkistan — 

 Past and Present. 



Malacological Society, at €.- G. B. Sowerby : A New Species of 

 AmpuUaria in the Geneva Museum. — Dr. A. E. Boycott : Parthenogenesis 

 in Faludestrinajenkinsi. — Tom Iredale : Notes on the Mollusca of Lord 

 Howe Island. 



SATURDAY, May 10. 



Royal Institution, at 3.— Pro*'. H. S. Foxwell : Chapters in the Psycho- 

 logy of Industry'. 



CONTENTS. PAGE 



The Complete Physical Chemist. By A. M. W. . i6i 



Acidosis. By Dr. J. S. Haldane, F.R.S. ... 162 

 Tropisms. By Prof. D'Arcy W. Thompson, C.B., 



F.R.S 163 



Our Bookshelf 164 



Letters to the Editor : — 



The Doppler Effect in the Molecular Scattering of 

 Radiation.— Prof. C. V. Raman ; Sir Joseph 



Larmor, M.P., F.R.S 165 



Indian Astronomical Instruments. (Illustrated.) 



By Dr. J. L. E. Dreyer .166 



The Occlusion of Gases by Metals. By H. C. H. C. 168 

 Prof. J. J. T. Schlcesing. By Dr. E. J. Russell, 



F.R.S 169 



Notes . 170 



Our Astronomical Column : — 



The April Meteors of 1919 I74 



The Meteoric Shower of Halley's Comet 174 



Occultation of Stars by Venus 1 74 



Civilian Air Routes. {IVith Map.) 175 



Forestry Research in Sweden 175 



Plantation Rubber Research. By H. W 176 



The Sensitiveness of Photographic Plates to 



X-Rays. By Miss N. C. B. Allen and Prof. T. H. 



Laby I77 



Rainfall Variations . . .... , . 177 



University and Educational Intelligence 178 



Societies and Academies 178 



Books Received 180 



Diary of Societies 180 



Editorial and Publishing Offices: 

 MACMILLAN AND CO., Ltd., 

 MARTIN'S STREET, LONDON, W.C.2. 



ST. 



Advertisements and business letters to be addressed to the 

 Publishers. 



NO. 2583, VOL. 103] 



Editorial Communications to the Editor. 

 Telegraphic Address : Phusis, London. 

 Telephone Number: Gerrard 8830. 



