August 4, 1923] 



NATURE 



165 



value and made it possible to obtain insulin from 

 animal pancreas in quantities for practical use. He 

 expected to find an insulin-like substance wherever 

 glycogen occurred in Nature, and for this reason 

 looked for it in vegetable extracts. Our belief that 

 oxidising ferments cause glucose metabolism led us 

 to examine vegetables for these ferments and for 

 substances with an insulin-like action. It seems that 

 CoUip's theory and ours dovetail. A storehouse of 

 food (glycogen, starch, etc.) and a ferment for the 

 metabolism of this food are necessary wherever 

 growth occurs in vegetables. 



Our studies have led us to the tentative suggestion 

 that insulin, which is apparently not itself an oxidase 

 or peroxidase, indirectly stimulates or activates 

 oxidising ferments in the tissue cells to action upon 

 glucose, whereas vegetable extracts contain active 

 oxidising ferments and act directly when injected 

 into animals. 



It would seem that the work of Winter and Smith, 

 of Collip, and of ourselves was being carried on 

 simultaneously and independently. Collip, very 

 properly, suggests that " These authors [Winter and 

 Smith] would, therefore, share coincident priority 

 with me in this particular." We think that we 

 should be included in this share of priority. 



William Thallinner. 

 Margaret C. Perry. 



Laboratories of Columbia Hospital, 

 Milwaukee, Wis., June 20. 



Scientific Names of Greek Derivation. 



Dr. J. W. Evans's letter in Nature (July 7, p. 9) 

 may serve as an excuse for commenting on certain 

 names which have recently been introduced into zoo- 

 logical literature without sufficient regard for etymo- 

 logical principles. Bathosella and Leiosella (Polyzoa) 

 may be given as examples of a series of new genera, 

 proposed in 1917 and later years, with the deriva- 

 tions, as stated, bathos, depth, and leios, smooth, 

 respectively. In these genera the entire Greek 

 word is used, instead of its root, and the generic 

 name is completed by the addition of a Latin diminu- 

 tive termination. The sufhx -sella is in any case 

 likely to cause confusion in Polyzoa, among which 

 -cella is the termination of many familiar generic 

 names. 



A second series of new genera ending in -nea is 

 also of recent introduction, to express an affinity to 

 Idmonea, which was presumably based on 'iotxwv. 

 ^lesonea and Pleuronea may be mentioned as ex- 

 amples of this misused employment of -nea. A 

 third unfortunate suggestion has just been made, to 

 the effect that the Latinised form of ^ivos or ^eV?? (a 

 guest) should be added to the generic name of a host, 

 in forming the trivial name of its parasite. Among 

 the illustrations of this supposed emendation in 

 nomenclature are ranaxena and bufoxena, both based 

 on Latin words. 



According to the Rules of Nomenclature, generic 

 and trivial names cannot be rejected on purely 

 etymological grounds. The same rules do not apply 

 to group-names, and it is accordingly justifiable to 

 suggest that some of them may be amended ; for 

 example, that Aplousobranchiata, which has been 

 proposed in Tunicata, should be replaced by the 

 more euphonious name Haplobranchiata. 



Dr. W. D. Lang {Geol. Mag., N.S., December, vol. 

 iv., 191 7, p. 282) has previously discussed some of the 

 points I have indicated. It may be useful, however, 

 to raise a protest against the continued introduction 

 of names formed in defiance of accepted principles, 



NO. 2805, VOL. I 12] 



and I venture to think that this practice will not tend 

 to raise scientific nomenclature in the estimation of 

 scholars. Sidney F. Harmer. 



British Museum (Natural History), 

 July 7- 



In 1844 Sir John Herschel wrote to Owen regretting 

 his spelling of the name of the fossil bird Dinornis, 

 and urged that a Frenchman would pronounce the 

 word Denornis, which he would not do had it been 

 spelt Deinornis. To this Owen answered by directing 

 attention to our pronunciation of the word receive. 



Herschel does not seem to have retorted, but he 

 might have done so by quoting — 



" segnius irritant animos demissa per aurem 

 quam quae sunt oculis subiecta fidelibus et quae 

 ipse sibi tradit spectator." 



And the retort would have been final. 



F. Jeffrey Bell. 

 The Athenaeum, Pall Mall, S.W.i, 

 July 8. 



The Scattering of Light by Anisotropic Molecules. 



Prof. L. V. King's interesting letter on this subject 

 in Nature of May 19, p. 667, calls for comment, as his 

 results do not seem to be acceptable in the light of the 

 work carried out at Calcutta in this field during the 

 past two years. 



Any proposed scattering formula should satisfy two 

 simple tests, namely, that for a fluid consisting of 

 isotropic molecules it should reduce to the Einstein 

 formula, and that for a sufficiently rarefied fluid it 

 should become the Rayleigh law of scattering. Prof. 

 King's formula (3) satisfies neither of these tests, as can 

 easily be seen on putting p =0 in it. The appearance 

 of the adiabatic compressibility in the formula is 

 inconsistent with thermodynamic principles . Einstein 

 has very clearly pointed out that the expression for 

 scattering must involve the isothermal and not the 

 adiabatic compressibility. Further, the omission 

 by Prof. King of the factor (m*^ +2)^/9 which appears 

 in Einstein's formula, cannot be reconciled with the 

 acceptance of the Lorentz refraction formula for a 

 fluid consisting of isotropic molecules. 



Prof. King's explanation of the diminution in the 

 depolarisation in the case of liquids, which occurs as 

 the critical temperature is approached, as due to the 

 breaking up of crystalline aggregates, seems inappro- 

 priate in view of the fact that a precisely similar effect 

 is shown by vapours, where obviously the conception 

 of crystalline aggregates is entirely out of place. Mr. 

 Ramanathan's paper on the scattering of light in 

 benzene vapour at high temperatures, which is appear- 

 ing in the Physical Review, clearly illustrates this. 

 The effects observed both in liquids and vapours have 

 been very simply explained without recourse to 

 artificial hypotheses in my papers in the Phil. Mag. 

 for January and March, where quantitative data 

 strongly supporting Einstein's formulae are set out. 



The fundamental error in Prof. King's reasoning 

 seems to arise at the point where he suggests that a 

 fluid consisting of comparatively stationary aniso- 

 tropic molecules, with equally probable orientations 

 in all directions, would scatter only polarised light. 

 This is certainly not the case. It can easily be seen 

 on resolving the effect due to an aelotropic molecule 

 oriented arbitrarily that the components perpendicular 

 to the light vector in the incident wave are affected 

 with a sign which may be either positive or negative 

 at random, i.e. irrespective of the position of the 



E 2 



