NA TURE 



[October i8, 1906 



to relegate the rare and occasional visitors — often of 

 the utmost interest — to a future supplement, which 

 will enhance the expense. 



To the eye of an artist the plates will doubtless 

 appeal as admirable specimens of the process 

 einploved, but to that of an ornithologist they lack 

 the life and vigour which in many cases compensate 

 for an absence of coloration. 



Finally, we quite agree with Mr. Stonham that in 

 many species the female and young are well worth 

 depicting, and that it is quite useless to attempt to 

 represent the songs of most birds by a set of syllables 

 which each reader would in all probability mouth 

 differently. 

 The Manufacture of Concrete Blocks, and their Use 



in Buitdiug Construction. By H. H. Rice and 



\V. M. Torrance. Pp. 122. (London : Archibald 



Constable and Co., Ltd., 1906.) Price Si. net. 

 This work is a reprint in full of the two prize papers 

 on concrete block construction in connection with a 

 competition instituted by the Engineering News and 

 the Cement Age, and, in addition, abstracts are given 

 of the papers of ten other competitors, which contain 

 data not given in the prize papers. 



Mr. Ri^e in his paper deals fully with the raw 

 materials — cement, sand and gravel, or crushed stone; 

 with the mixing and manufacture of the blocks; and 

 with the important questions of curing and facing the 

 blocks with a finer quality of the material, and he 

 briefly discusses the principles underlying the use of 

 this material in building construction. 



Mr. Torrance deals more fully With the form of 

 the blocks, illustrations being given of many of the 

 moulds for which patents have been granted, and 

 with the relative cost of buildings of concrete and 

 other material; finally, he states that from an artistic 

 standpoint the best success so far obtained has been 

 where the process of casting in sand has been adopted, 

 and several reproductions of photographs are given 

 to illustrate this point. 



The abstracts of the other ten papers give much 

 useful information on many points of detail not dealt 

 with bv the authors of the two prize papers, with re- 

 gard both to the manufacture of the blocks and also 

 to their employment in building construction. 



In an appendix are the rules and regulations govern- 

 ing the use of this material and the testing of the 

 blocks in Philadelphia. There has been quite a flood 

 of literature during the past year on reinforced con- 

 crete, but until this book apjieared little had been 

 written in reference to the use of concrete by itself 

 for building purposes. 

 Elementary Electrical Calculations. By W. H. N. 



James and D. L. Sands. Pp. 216. (London: 



Longmans, Green and Co., 1905.) Price 3^. 6d. 



net. 

 This book is based upon a series of lectures given by 

 the authors to first- and second-year students of elec- 

 trical engineering, and can be confidently recom- 

 mended to those for whom it is written. So far as 

 it goes, it is well arranged and perfectly clear ; the 

 only criticism that can be suggested is that it does 

 not go far enough. The range of a subject which 

 should be studied by first- and second-year students 

 is, however, a matter for individual teachers to settle. 



It will suffice, therefore, to state that the book 

 begins with an account of the fundamental units, 

 proceeds to discuss Ohm's law very fully, and devotes 

 brief chapters to power and work, conversion of 

 energy, transmission and distribution treated quite 

 simply, electrochemistry and photometry. Each 

 chapter contains numerous examples fully worked 

 out, and a large number of exercises for the student. 



NO. 1929, VOL. 74] 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 /nanuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Biometry and Biology: A Rejoinder. 



I SHOULD like to preface my remarks on Mr. Lister's 

 reply by relieving his mind from any anxiety about Dr. 

 Pearl's feelings. Dr. Pearl is in .America, and I cannot, 

 of course, communicate with him, but I know him 

 intimately, and am convinced that he is far too good 

 a man of science to feel aggrieved by any criticism of his 

 writings. He might well feel aggrieved that Mr. Lister 

 supposes him desirous that his paper should remain un- 

 criticised, because the criticism should affect his reputa- 

 tion. I am inclined to think that, as a fellow biometrician, 

 he will rejoice with me that Mr. Lister's vague charge — 

 made at a singularly unfitting moment — has been brought 

 to a definite issue, and can be tried coram judice. 



Had a first-year biometrical student in my laboratory 

 sought advice from a biological freshman about the nature 

 of Paranmeciiim caudatum, I should have anticipated that 

 he would receive much the information with which Mr. 

 Lister provides us. His remarks could only be made by 

 one who (a) had either not studied the memoir he 

 criticises, or had failed to perceive the significance of the 

 constants calculated by the author, and (b) had never 

 attempted accurate measurements on infusoria, or previously 

 to such attempt been trained to that caution and accuracy 

 in measurement which it is the function of biometry to 

 inculcate. 



I challenged Mr. Lister to substantiate the charge he 

 made in .'\ugust, when, presumably, the grounds of his 

 insinuation at York were fresh in his mind. He then 

 considered that Dr. Pearl's position was traversed by the 

 objection that the conjugants individually are possibly or 

 probably differentiated gametes. 



What was the author's position? He expresses it 

 exactly by quotations from Huxley and Romanes : — 



" In my earliest criticisms of the ' Origin ' I ventured 

 to point out that its logical foundation was insecure so 

 long as experiments in selective breeding had not produced 

 varieties which were more or less infertile, and that in- 

 security remains up to the present time " (Huxley, " Life 

 and Letters of Darwin," vol. i., p. 170). 



" To state the case in the most general terms we may 

 say that if the two basal principles are given in heredity 

 and variability, the whole theory of organic evolution 

 becomes neither more nor less than a theory of homogamy 

 — that is a theory of the causes which lead to discriminate 

 isolation, or the breeding of like with like to the exclusion 

 of unlike " (Romanes, " Physiological Selection "). 



This problem of the divergence of individuals into varie- 

 ties is the one selected by Dr. Pearl, and according to 

 Mr. Lister is the best example by which he can illustrate 

 his statement that biometricians do not select a sound 

 biological problem " before bringing a formidable mathe- 

 matical apparatus into action for its investigation." This 

 is ihr " hare cooked before it was caught," to cite again 

 Mr. Lister's phrase. Dr. Pearl shows that such homogamy 

 exists in an extraordinarily high degree in Paramaccium 

 caudatum. In other words, he has broken entirely novel 

 ground, which, to say the least of it, renders Huxley's 

 position no longer tenable. This is now admitted, albeit 

 in a niggardly fashion, by Mr. Lister himself. In .August 

 he considered that Dr. Pearl's position was traversed by 

 his omission to consider the differentiation of gametes 

 which was possible or probable. He does not now even 

 endeavour to show that it is traversed by this, but says 

 that I have claimed for Dr. Pearl the first demonstration 

 of the existence of this differentiation. In other words, 

 he now admits that Dr. Pearl has fully considered the 

 problem of differentiation. In fact, more than half Dr. 

 Pearl's memoir is devoted to it. He further twits Dr. 

 Pearl and myself with not distinguishing between a man 

 :md his gamete ! 



• : on 



