July 28, 1923] 



NATURE 



133 



with the ultramicroscope as ordinarily used. One 

 can, I think, see a dim suggestion of the fluorescence 

 colour in isolated chloroplasts (Elodea), and in the 

 chloroplast of Spirogyra, but when in situ the 

 multitude of reflecting surfaces produces so much 

 transmitted light that the fluorescence is masked by 

 the green coloration. 



It was, therefore, of no small interest to find also 

 that the pigment in the oil vacuoles of the diatoms, 

 pale greenish-yellow by transmitted light, is also 

 visibly deep red fluorescent when viewed in the 

 manner above described. Glycerin must be used 

 as a mounting medium. Examined thus, the 

 fluorescent pigment is seen to fill vacuoles, large 

 and small. I have found that this pigment is not 

 destroyed at the temperature of boiling water, 

 whereas phycocyanin changes at about 60° C. ir- 

 reversibly, and loses its fluorescence. It may be the 

 phycocyanin-like pigment found by Bocat (through 

 Czapek, " Biochemie des Pflanzen," i : 601) in 

 Navicula, which, as a matter of fact, has two large 

 fluorescent vacuoles and usually two small ones, one 

 near each end of the cell. 



Scenedesmus glows with a deep red light, as also 

 a small species of Raphidium (or closely similar 

 organism). I have found further evidence of fluor- 

 escence in other green forms, notably an ulvaceous 

 one. 



Many beautiful results will reward the microscopist 

 who will use the method. Especially, one can 

 scarcely contemplate the remarkable irradiance of 

 these lowly plants without realising anew the im- 

 portance of the problem of the physiological signi- 

 ficance of fluorescence. In a paper presented at 

 the recent meeting of the Royal Society of Canada, 

 I have endeavoured to discuss the matter in its 

 more general bearings. The immediate purpose is 

 to direct attention to a means of increasing the 

 usefulness of the dark-field condenser. 



Francis E. Lloyd. 



McGill University, Montreal, June i. 



Dr. Kammerer's Lecture to the Linnean Society. 



I AM very sorry to differ from my friend Prof. 

 MacBride, but it is impossible for me to agree with 

 some of his remarks on Dr. Kammerer's recent 

 lecture (Nature, June 23, p. 841). I did not assert 

 that Dr. Kammerer made " childish mistakes which 

 would disgrace a first-year student in biology." I 

 expressed my opinion that it was not correct to state 

 that the ovary of Salamandra is enclosed in a mem- 

 brane while that of the bird is not. I fail to see why 

 Dr. Kammerer's statement should require to be trans- 

 lated into modern technical language. It is a some- 

 what serious suggestion that he cannot express his 

 ideas in such language for himself, and if that be so, 

 it supports my criticism that in some respects his 

 statements were not in accordance with the present 

 state of biological knowledge. 



I cannot, however, accept even Prof. MacBride's 

 description of the condition of the ovary of the bird 

 as correct (and I dissected out the ovary of a common 

 hen to-day, not for the first time) . The ovary of the 

 bird is almost as completely invested by peritoneum 

 as that of the Salamander, not only on its ventral 

 surface but on its lateral surfaces also, and it is not 

 largely retroperitoneal. I agree that the ovary of the 

 bird is more difficult to remove in its entirety, because 

 it is sessile on the peritoneum, and not connected with 

 it by a membrane, and still more because its attach- 

 ment is close to the great post-caval vein, so that it is 

 difficult to remove the part by which it is attached 

 without cutting into the vein. To be strictly correct, 

 the narrow membrane which attaches the ovary to the 



NO. 2804, VOL. I 12] 



wall of the body cavity in Salamandra is not a 

 mesentery, as Prof. MacBride calls it, because that 

 term means a membrane connected with the intestine. 



It would serve no useful purpose to reply to other 

 points in Prof. MacBride's letter. He refers me to 

 Dr. Kammerer's " long paper." But I was dealing 

 with the lecture as delivered and printed, which in 

 my opinion failed to show that Dr. Kammerer had 

 an adequate conception of the range of knowledge, 

 the completeness of evidence, and the validity of 

 reasoning, required to establish the conclusions he 

 asks us to accept. I am not, of course, suggesting 

 any deception on Dr. Kammerer's part — except self- 

 deception. Lamarckian doctrine has often suffered 

 more from the indiscretion of its advocates than 

 from the attacks of its enemies. 



J. T. Cunningham. 



East London College, Mile End, E.i, 

 June 26. 



The British Jdumal of Experimental Biology. 



Though British workers have made some of the 

 most signal contributions to the morphological aspects 

 of zoology, and names like those of Romanes, Bateson, 

 Doncaster, and Geoffrey Smith will always be dis- 

 tinguished for pioneer discoveries in the experimental 

 field. Great Britain at the present moment compares 

 very unfavourably with other countries in facilities 

 for the publication of researches in experimental 

 biology, especially on the zoological side. There is 

 no single journal devoted wholly or mainly to the 

 subject, with the exception of the Journal of Genetics, 

 which of course only covers a portion of the field. 

 We have in Great Britain nothing to compare, for 

 example, with the Journal of Experimental Zoology, 

 the Biological Bulletin, and the Journal of General 

 Physiology in America, or with the Archiv fiir Entwick- 

 lungsmechanik in Germany and the French Archives 

 de morphologic experimentale. Nor have we any 

 biological journal which makes it a regular practice 

 to publish articles of a general nature summarising 

 and discussing critically recent additions to know- 

 ledge, as in the American Naturalist and the Refer aten 

 of several continental journals. 



In the absence of an adequate medium of publica- 

 tion in Great Britain, experimental biologists do not 

 know sufficiently what work is in progress, with the 

 natural result that there is overlapping ; that 

 experimental inquiry, lacking a satisfactory channel 

 of expression, may fail to exert an influence essential 

 for the further development of biology in Great 

 Britain ; and that younger men will tend to migrate 

 from the zoological laboratories to associate themselves 

 with departments of human physiology. Biological 

 science is at present passing through a period of 

 transition : on one hand, it is becoming increas- 

 ingly clear that the problems of evolution can no 

 longer be dealt with adequately from the traditional 

 morphological and descriptive point of view of 

 zoology ; on the other, the adoption of experimental 

 methods by the general zoologist is opening up new 

 fields of research and making it possible to study 

 more readily the nature of many fundamental 

 biological processes, such as fertilisation, development, 

 sex and heredity, which have been too often neglected 

 by traditional physiology. In the words of a dis- 

 tinguished morphologist, there is a growing tendency 

 " to return to the practice of earlier days, when 

 animal physiology was not yet divorced from 

 morphology." 



We believe that the time has now come when it is 

 possible to issue a British journal devoted to general 

 biology, in particular to experimental research and to 



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