4-3- 



NATURE 



[September 3, 1903 



bridge, and Miss E. G. Willcock, Newnham College, 

 Cambridge. 



A solution of iodoform dissolved in chloroform rapidly 

 becomes purple owing to the liberation of free iodine. This 

 reaction, which seems not to have been previously described, 

 takes place in all the solvents tried, namely, chloroform, 

 benzene, carbon bisulphide, carbon tetrachloride, pyridine, 

 amyl alcohol, and ethylic alcohol, but oxygen is always 

 necessary to the change. 



The decomposition of iodoform in solution is not, as it 

 at first sight appears to be, a spontaneous change. It is 

 due ordinarily to the action of light. The solvent has a 

 great effect on the rate of decomposition — the solution in 

 chloroform is very sensitive, that in benzene relatively 

 stable. The solution in chloroform furnishes a delicate 

 tegt for oxygen and for obscure radiations. It suffers 

 change in gas light, faint daylight, and in X-rays or radium 

 rays. The intensity of the action can easily be measured 

 in time units by choosing some standard coloi^r and match- 

 ing the fluids under examination with it. 



The action of light is due to the ordinary light waves, 

 that is to say, any opaque screen completely arrests the 

 action even of sunlight. Solutions in chloroform enclosed 

 in opaque cardboard boxes have remained, unchanged near 

 a window for four days. 



The action of radium is due to the more penetrating rays. 

 By screening off the various rays, it can be shown that the 

 a rays have no influence — the oxidation appears to be due 

 solely to the /8 apd 7 rays, that is, to the negative electrons 

 (j3 rays) and to the very penetrating ethereal waves (7 rays), 

 which are said to be identical with X-rays. The action 

 of the radium rays, therefore, will take place through as 

 much as 8mm. of lead, though, of course, relatively very 

 slowly, owing to the stopping of the /3 rays. 



Some idea of the intensity of the action of radium may 

 be obtained from the fact that a solution in chloroform in 

 an ordinary test tube is changed to deep purple in twelve 

 minutes by resting the point of the tube upon a mica plate 

 covering -5 milligrammes of radium bromide. Radium rays, 

 however, are much less active than daylight, as is shown 

 by the fact that the more stable solution of iodoform in 

 benzene resists their action for forty-eight hours, though it 

 becomes purple in about fifteen minutes in the least lighted 

 part of an ordinary room. Seeing that the thinnest opaque 

 screen seems completely to stop the active rays of sunlight, 

 it is obvious that sunlight, as it reaches the surface of the 

 earth, can contain at the most exceedingly few /8 and 7 

 rays. 



M. Blondlot has described recently the presence in sun- 

 light of certain rays which traverse metals but are arrested 

 by water (N rays). These rays have no detectable action 

 upon iodoform ; the action of sunlight is not delayed appreci- 

 ably by interposing a water screen many inches in thick- 

 ness, and the action is completely arrested by even an 

 opaque deposit of lampblack or by aluminium foil. 



The fact that light waves ' exert a chemical activity more 

 intense than that of radium rays compels us for the present 

 to refer the profound, and often lethal, physiological action 

 of the latter to their power of penetration rather than to 

 any novel or peculiarly intense action upon the tissues. 

 They reach parts which ordinarily are shielded by a cuticle 

 impervious to light waves. 



One of us has already shown that the o rays profoundlv 

 modify the physical state of colloidal solutions (Journal of 

 Physiology, vol. xxix. p. 29). If the colloid particles be 

 electrically negative, the o rays act as coagulants; if the 

 colloid particles be electrically positive they act as solvents, 

 that is to say, the rays decrease the average size of the 

 particles. 



As a provisional basis for the investigation of the physio- 

 logical action of radium rays, we may therefore regard 

 the a rays as altering the physical state of the living 

 matter, the $ and 7 rays as altering the chemical 

 processes, especially, perhaps, the oxidation processes of the 



let waves. Hardy and D'Arcy have 



I Including of course, the utra violet ....... ..„,„^ „.,„ ^ „„y „,,, 



shown that the production of "active" oxygen by light falling upon a 

 moist surface IS limited m the spectrum to rays from the ultra-violet to the 

 blue end of the green {Journal of Physiology, xvii. 1894, p. 390) 



NO. 1766, VOL. 68] 



Paris. 

 Academy of Sciences, August 24. — M. Albeit Gaudry in 

 the chair. — Batteries with several different liquids, but 

 identical . metallic electrodes, byM. Berthelot. — Observ- 

 ations of the sun made at the Observatory of Lygns with 

 the Briinner ^6cm. equatoriar during the second quarter of 

 1903, by M. J. Guillaume. Observations were possible 

 on sixty-seven days during the quarter • the results are 

 given in three tables showing the number of sun-spots, 

 their distribution in latitude, and the distribution of the 

 faculae in latitude.— On the problem of S. Lie, by M. N. 

 Saltykovw. — On the Fourier-Cauchy integrals, by M. Carl 

 St6rmer.^-On the function of the metallic core in induction 

 coils, by M.. B. E^rinitis. The effect of the core varies 

 with its shape, material, the temperature of the sparking 

 poles, their nature and explosive distance, and also on the 

 self-induction of the coil. — On the constitution of the 

 phospho-organic acid in the reserve material of green 

 plants, and on the first reduction product of carbonic acid 

 in the act of. chlorophyll assimilation, by M. S. Posternak. 

 The acid, heated with dilute mineral acids, is quantitatively 

 hydrolysed into, inosite and phosphoric acid. From this, 

 and its crvoscopic behaviour in aqueous solution, the 

 formula 0[CH,.O.PO(OH)2]2, the anhydride of oxymethyl- 

 ene-diphosphoric acid, is given to the substance, and con- 

 clusions are drawn from this as to the nature of chlorophyll 

 assimilation. — On the general equation of curves of fatigue, 

 by M. Charles Henry and Mile. J. Joteyko. 



CONTENTS. PAGE 



Psychometric Observations in Murray Island. By 



F. G. . 409 



A Revision of Principles. By R. W. H. T. H. . . . 410 

 Electrochemical Analysis. By Dr. F. MoUwo 



Perkin 41 2 



Tectonics of the Eastern Alps. By G. A. J. C. . . 413 

 Our Book Shelf:— 



Ebner : " A Koelliker's Handbuch der Gewebelehre 



des Menschen." — E. A. S 414 



Clark: '* Building Superintendence' 414 



Pradeau : "A Key to the Time Allusions in the 



Divine Comedy of Dante Alighieri." — W. T. L. , 414 



Hall and Stevens : *'A School Geometry," Part iii . 415 

 Letters to the Editor : — 



American Botanic Laboratory in Jamaica. — N, L. 



Britton ........ 415 



Training of Fore«t Officers. — Sir W. T, Thiselton- 



Dyer, K.C.M.G.. F.R.S 416 



Peculiar Clouds.— Alfred O. Walker 416 



The Earthquake Observatory in Strassburg . . . . 416 



The International Study of the Sea 417 



Arctic Geology. {Illustraled.) By Prof. T. G. 



Bonney, F.R S 418 



Fisheries Investigation in Ireland. By W A. H. . 419 

 The Sanitary Examination of Water Supplies. By 



Prof. R, T. Hewlett . 420 



Notes 420 



Our Astronomical Column : — 



Spectrum of Comet 1903 c 424 



The Spectrum of Nova Geminorum ........ 425 



United States Naval Observatory 425 



The White Spots on Saturn 425 



The Teaching of Psychology in Universities of the ■ 



United States. By Dr. C. S. Myers ...... 425 



American Ethnology. By A. C. H 427 



Agricultural Notes . . 427 



Report of the Malaria Expedition to the Gambia . 428 



Zones in the Chalk. By H. B. W. . . , 428 



The Physiology of Breeding 429 



University and Educational Intelligence ..... 429 



Societies and Academies 430 



