August 26, 1920] 



NATURE 



843 



impression that explosive sounds travel much farther 

 than do ordinary sounds, the velocity being, perhaps, 

 several times the normal velocity. Ihese experiments 

 show conclusively that the velocity at a distance of 

 100 ft. from a lo-in. gun is about 1240 It. per second, 

 or 22 per cent, above normal ; at 200 ft. from the 

 gun the velocity is only about 5 per cent, above 

 normal. For all distances above 500 ft. from the 

 gun the velocity of the explosive sound from the 

 largest-sized gun is practically normal.— Dr. H. C. 

 Hayes : The U.S. Navy MV-type of hydrophone as 

 an aid and safeguard to navigation.- — Dr. A. E. 

 Kennelly : The transient process of establishing a 

 steady alternating electric current on a long line from 

 laboratory measurements on an artificial line. It is 

 known that the current and voltage do not build up 

 steadily and continuously, but advance by little jumps 

 which occur at regular short intervals of time, accom- 

 panying- successive reflections of electromagnetic waves 

 from one end of the line to the other. There is pre- 

 sented in this paper a number of observations which 

 have been secured photographically of the rise of 

 voltage and current on a long artificial electric power 

 transmission line in the laboratory, and have com- 

 pared the observed rates of growth with those which 

 are indicated bv theory with a fairly satisfactory 

 agreement. — N. W. Akimoff : The strephoscope. — 

 Prof. R. S. Dugan : New features in the eclipsing 

 variable U Cephei. (Prof. W. B. Scott, presi- 

 dent, in the chair.)— Prof. E. N. Harvey: Animal 

 luminescence and stimulation. The production of 

 light by animals is due to the burning or oxidation 

 of a substance called luciferin in the presence of an 

 enzyme or catslvst called luciferase. Light produc- 

 tion bv animals differs from light produced by com- 

 bustion in that the oxidation product of luciferin, 

 oxyluciferin, can be easily reduced to luciferin, which 

 will again oxidise with light production. The reaction 

 is reversible, and appears to be of this nature : 

 luciferin + Oz^oxvluciferin-t-H,0. The difference be- 

 tween luciferin and oxyluciferin lies probably in this : 

 that the luciferin possesses two atoms of hydrogen, 

 which is removed to form H^O when the luciferin 

 is oxidised. The H, must be added to re-form luci- 

 ferin. Not only is it most efficient so far as the 

 radiation (being all light) it produces is concerned, 

 it is also most economical so far as its chemical pro- 

 cesses are concerned. The above reactions can be 

 demonstrated in a test-tube with a mixture of oxy- 

 luciferin, luciferase, and ammonium sulphide. The 

 ammonium sulphide is probably represented in living 

 cells bv reducing enzvmes or reductases. If such a 

 test-tube is allowed to stand, oxyluciferin is reduced 

 to luciferin, which will luminesce only at the surface 

 of the fluid in the test-tube in contact with air. 

 When the tube is agitated so as to dissolve more 

 oxygen of the air, the liquid g-lovi's throughout. Even 

 a gentle knock or "stimulus " to the tube is suflficient 

 to cause enouf*h oxygen to dissolve to give a momen- 

 tary flash of lif'ht which is strikinglv similar to the 

 flash of light given by luminous animals themselves 

 on stimulation. This sufgests that when we agitate 

 a luminous animal, or when the luminous gland-cells 

 of a fireflv are stimulated through nerves, with the 

 resultant flash of light, in each case the stimulus acts 

 bv increasing the permeability of the surface-laver of 

 the cells to oxygen. This then upsets an equilibrium 

 involving the luciferin, luciferase, oxvluciferin, oxygen, 

 and reductase within the cell, with the production 

 of lipht and the formation of more oxvluciferin. 

 So Ion? as the luminous cell is resting- and unstimu- 

 lated, the tendency is for reduction processes to occur 

 and luciferin to be formed. It must be pointed out 

 that not all sorts of stimulation can be explained in 



NO. 2652, VOL. IO5I 



this way, as the stimulation of muscles or nerve-fibres 

 may take place in the complete absence of oxygen. — 

 Prof. G. H. Parker: The phosphorescence of Renilla. 

 During the day Renilla cannot be excited to phos- 

 phoresce, but at night on stimulation it can be made 

 to glow with a beautiful golden-green light. The 

 light is produced in wave-like ripples that spread out 

 from the spot stimulated and run over the upper 

 surface of the animal. They travel at a relatively 

 slow rate that agrees with that at which the nervous 

 impulses of the animal travel. Hence it is concluded 

 that the phosphorescence of Renilla is under the con- 

 trol of the nerve-net of the animal, which apparently 

 pervades the whole colony.— Prof. W. M. Wheeler and 

 I. W. Bailey : Feeding habits of Pseudomyrmine ants. 

 Examination of the mouth of the larva reveals a singu- 

 lar hitherto undescribed organ, evidently used for reduc- 

 ing the food-pellet to such a finely divided state that 

 it can, when acted upon by the digestive juices of the 

 stomach, yield a certain amount of nutriment which 

 the worker-ant could not extract from it while it 

 was in the infrabuccal pocket. This larval organ rnay 

 be called the trophorhinium. In all Pseudomyrmine 

 larvae, and in many larvae of the other sub-families, 

 except the Dorylinae and Cerapachyinae, the tropho- 

 rhinium is beautifully developed, although in many 

 ants (Ponerinae) it must be used for comminuting 

 parts of insects given directly to the larvae bv the 

 workers. In its development the trophorhinium bears 

 a strange resemblance to the stridulatory organs of 

 the petiole and post-petiole of many adult ants. — Dr. 

 S.. E. Ortmann : Correlation of shape and station in 

 fresh-water mussels. It has been found that for 

 certain species more swollen specimens are found 

 down-stream in the larger rivers and more compressed 

 sf>ecimens more up-stream, and that in the inter- 

 mediate stretches of a* river these extremes are con- 

 nected by gradual transitions. — Prof. H. F. Osborn : 

 Evolution principles deduced from a study of the 

 even-toed Ungulates known as Titanotheres. — Prof. 

 W. B. Scott : The Astropotheria.— B. F. Howell, jun. : 

 The Middle Cambrian beds at Manuels, Newfound- 

 land, and their relations. These beds are of special 

 scientific interest because they contain large numbers 

 of unusually well-preserved fossils, which prove that 

 the creatures that swarmed in the waters then cover- 

 ing much of what is now New England, south-eastern 

 Canada, and south-eastern Newfoundland were of 

 practically the same sort as those living in the seas 

 which at the same period washed over many parts of 

 Scandinavia and the British Isles. North America 

 has probably been joined to Europe in this way several 

 times in the geolog^ical oast, so that the animals living 

 in the coastal waters could spread from one hemi- 

 snhere to the other.— Prof. W. H. Hobbs : (i) The 

 Michif^an meteor of November 26. iqiq. (2) The 

 flacial anticyclone and the blizzard in relation to the 

 domed surface of continental glaciers. 



Rome. 

 Reale Accademia del Lincei, March 7. — k. R6iti, vice- 

 president, in the chair. — Q. Majorana : Gravitation, 

 viii. — O. Chisini : Analytic representation of the fold 

 of a surface by a series of fractional powers of two 

 variables. — U. CI»otti : Integration of the equation 

 of wave-motion in a deep canal, ii. The equation of 

 the free surface is determined. — O. Onlcescu : New- 

 tonian fields in the neighbourhood of a given vectorial 

 field. Sx\ application of I^vi-Civita's notion of 

 harmonics in the neiehbourhood of an assigned func- 

 tion. The author deduces the lamellar and solenoidal 

 magnetisation which gives rise to a given magnetic 

 field, and applies the result to deal with the existence 

 and unique nature of the magnetisation in soft iron. 



