December 15, 1923] 



NA TURE 



S^7 



four or six lines, and special sextic curves with many 

 simple geometrical properties, all connected with a 

 given confocal system of bicircular quartic curves. 



Manchester. 

 Literary and Philosophical Society, November 20. — 

 G. H Carpenter: Warble-flies of cattle. The larvae 

 of the two common species of Hypoderma [H. bovis De 

 Geer and H. lineatum Villers) are among the best- 

 known parasites of domestic cattle in the British 

 Isles, in Europe, and in North America ; their 

 economic importance is considerable on account of 

 the damage caused to flesh and hides by the large 

 maggots feeding just beneath the skin of the back 

 which they perforate, and also because of the loss 

 of condition suffered by the cattle when they " gad " 

 in summertime to escape from the female fly approach- 

 ing to lay her eggs. Observations carried on since 

 1905 by Carpenter and his colleagues in Ireland, by 

 Glaser in Germany, and by Seymour Hadwen in 

 Canada, have shown that the early life history of 

 these insects presents some surprising features. The 

 eggs of both species are generally laid on the legs 

 (from thigh to hoof), rarely on shoulder or flank, 

 never apparently on the back. By examination of 

 the skin after egg-laying and by means of a series 

 of experiments with calves, muzzled so that they 

 could not lick themselves or one another, it has been 

 demonstrated that the mode of entrance into the 

 host's body is not by the mouth. The eggs are 

 hatched on the hairs a few days after laying, and the 

 tiny maggots, less than a millimetre long and pro- 

 vided with strong, sharp mouth-hooks and relatively 

 formidable spiny armature, crawl along the hairs 

 and bore their way directly into the skin. Thence 

 they migrate upwards and forwards to the gullet- 

 wall, the sub-mucous coat of which serves as their 

 resting-place for some weeks or months in the course 

 of their journey through the host's tissues to the 

 final position in the back. The number of larval 

 stages is still to be determined. The gullet-maggot 

 is so much larger (up to half an inch) than the newly- 

 hatched maggot, that it has generally been regarded 

 as representing a second stage, but it possesses 

 mouth-hooks of the same size and form and a spiny 

 armature that is easily overlooked on account of the 

 increase in actual size of the larva, so that the spines 

 are relatively far apart. Hence Gedoelst has recently 

 argued that there is no " moult " between the newly- 

 hatched and the gullet-dwelling larva — only extra- 

 ordinary growth. On the other hand, Laake concludes 

 not only that the migrating maggot is a second 

 instar succeeding the newly-hatched insect that 

 bores in, but also that there is an antepenultimate 

 instar beneath the skin, differing from the migrating 

 maggot in the total absence of spines on the body- 

 segments. 



Paris. 



Academy of Sciences, November 19. — M. Albin 

 Haller in the chair. — G. Bigourdan : A project for a 

 French national biography. — M. Lecornu : Elastic 

 couplings. A mathematical discussion of the effect 

 of an elastic coupling between a dynamo and its 

 motor on the steadiness of rotation. It is shown to 

 be impossible to decide, in a general manner, whether 

 the elasticity of the coupling is or is not favourable 

 to the regularity of the motion of the dynamo. — 

 Charles Moureu, Charles Dufraisse, and Philippe 

 Landrieu : Remarks on the principle of a general 

 method for determining the heat capacity of solids 

 and liquids and its application to the determination 

 of the water value of calorimetric bombs. The 

 principle of the method suggested by the authors 

 in a previous communication {Comptes rendus, 176, 



NO. 2824, VOL. I 12] 



15 1 3) had been anticipated by Pfaundler (1869) and 

 Swietoslawski (1909). — Gabriel Bertrand : The trans- 

 port of copper in the gaseous state and copper- 

 carbonyl. M. Gelinsky has explained a curious 

 example of pseudomorphism by assuming the 

 volatihty of copper oxide. This would not appear 

 to be the true explanation of the phenomenon. 

 Copper oxide heated in a stream of either oxygen, 

 hydrogen, or carbon dioxide gives no appreciable 

 transport of the metal even after several hours. 

 But with carbon monoxide there is produced a 

 copper ring, apparently due to the formation of a 

 volatile copper-carbonyl, readily dissociated on 

 heating. The bearing of this observation on the 

 determination of traces of copper in organic substances 

 is indicated : with a brass burner and the material 

 exposed to the gases from the flame, copper may be 

 transferred from the burner to the ash. On the 

 other hand, carbon monoxide formed during the 

 combustion of the organic substance may carry 

 away traces of copper. — Paul Vuillemin : New proof 

 of the dystrophic origin of scyphia.— S. Winogradsky : 

 The direct method in the microbiological study of 

 the soil. The results of thirty years' work on the 

 microbiology of the soil are, in the author's view, 

 unsatisfactory. The conditions of culture in the 

 bacteriological laboratory are too far removed from 

 the conditions actually existing in the soil, and tend 

 to form new races of organisms distinct from the 

 types in the soil from which they were originally 

 obtained. A scheme of culture is proposed more 

 closely approximating to natural soil conditions. — 

 E. Baticle : A mode of compensation for shrinking 

 in concrete arches. — M. Mesnager : Remarks on 

 the preceding communication. — E. Huguenard, A. 

 Magnan, and A. Planiol : Research on the surplus 

 of power of birds in flight. — M. Delanghe : General 

 method for determining graphically the elements of 

 flight of an aeroplane. — Bernard Lyot : Study of 

 the planetary surfaces by polarisation. By the use 

 of a more sensitive polarising apparatus than that 

 hitherto employed, the proportions of polarised 

 light from the planets has been studied. Details of 

 70 observations on the planet Venus are given. — 

 J. Guillaume : Observations of the sun made at the 

 Observatory of Lyons during the second quarter 

 of 1923. Observations were possible on 86 days 

 during the quarter : the results are summarised in 

 three tables showing the number of spots, their 

 distribution in latitude, and the distribution of the 

 faculae in latitude. — J. de Schokalsky : The length 

 of the rivers of Asiatic Russia, and on the system of 

 measuring rivers on maps in general. — Maurice Curie : 

 Spark spectra in non-metals in the liquid state. 

 Studies of spark spectra between platinum points 

 in bromine, liquid oxygen, fused sulphur, liquid 

 nitrogen, and fused phosphorus. In all cases a 

 continuous spectrum was obtained. The absorption 

 bands of oxygen were clearly shown. — E. Brylinski : 

 Michelson's experiment and the contraction of 

 Lorentz. — h6on and Eugene Bloch : New extension 

 of the spark spectra of tin and zinc in the Schumann 

 region. Tables of wave-lengths of lines and in- 

 tensities are given for tin from \ = 1699 to 1305, for 

 zinc from X ^1556 to 1310. — R. de Mallemann :' The 

 electric double refraction of camphor and carvone. 

 — Edmond Bauer : The change of wave-length ac- 

 companying the diffusion of X-rays. — Jean Fallou : 

 A very simple method permitting the determination 

 experimentally of tlie dispersion reiictancc of triphase 

 alternators. — Adricn Karl and S. Lombard : The 

 estimation of radium in the natural titano-niobates. 

 The method is ba.sed on the removal of silica with 

 hydrofluoric acid, fusion with potassium bisulpliate, 

 addition of sulphates of sodium and lithium to lower 



