156 SCIENCE PROGRESS 



The subjects of the juvenile lectures include reflection and refraction, the visible 

 and invisible spectrum, polarisation and Rontgen light ; the wave theory is used 

 from the beginning. The lecture on radium is an interesting account of the first 

 discoveries in connection with this element. It is, of course, very short and 

 incomplete, written, as it was, six years ago. The last lecture, on the manufacture 

 of light, is an inquiry into the properties of our present modes of illumination 

 with a view to the discovery of one of higher efficiency. 



The whole forms an interesting and readable book. A text-book it does not 

 profess to be but the reader will find in its lucid summaries and simple expo- 

 sitions a means of clarifying confused ideas which may have been obtained from 

 the detailed accounts and technical language of more formal treatises. The 

 demonstrations are striking, instructive and described with sufficient detail to 

 enable any lecturer to repeat them. The book is very well printed and illustrated, 



and, within its limits, fulfils its purpose admirably. 



H. MOSS. 



Heredity in the Light of Recent Research. By L. Doncaster, M.A. The 

 Cambridge Manuals of Science and Literature. (Cambridge : at the 

 University Press, 1910. Price is.) 



We were told in our youth that oases are met with but infrequently in arid 

 deserts and are usually small : if this be the case the work before us may well 

 rank as an oasis in the vast desert of arid literature presented to readers in these 

 days. Mr. Roosevelt, in his African Game Trails, speaking of the books he 

 has carried with him on his travels, remarks : " I did not often take scientific 

 books simply because as yet scientific books rarely have literary value. Of 

 course a really good scientific book should be as interesting to read as any other 

 good book." Of course it should and if books can be produced like the all too 

 brief essay under notice the stigma attached by Mr. Roosevelt to scientific 

 books will be removed at no distant date, so that the Hunter-President will 

 be able to include some of them with Alice in Wonderland, Hack Finn and 

 Omar Khayyam in his "Pigskin Library" on his next expedition into the wilds 

 of Nature. 



No study can be of greater importance to mankind than that of Heredity. 

 The situation is pithily defined by Mr. Doncaster in a short reference he makes to 

 Eugenics, "the study, that is, of the methods by which the race may be improved 

 both physically and mentally." " The whole trend of the results obtained [he 

 says] is that in order to produce exceptionally gifted men in both body and mind, 

 those with high development of the characters desired should be encouraged to 

 marry; and that to prevent the production of the weakly and feeble-minded, the 

 only method is to \ prevent such from having offspring. It is admitted that at 

 present these things hardly come within 'practical politics' but there is little 

 doubt that the nation which first finds a way to make them practical will in a very 

 short time be the leader of the world." 



The only objection we are inclined to urge is that the book contains far too 

 many of the special terms with which the Mendelians have thought proper to 

 load the study of their subject— so much so that it may almost be supposed this 

 is done with the object of making it forbidding to the general public. No policy 

 could be more shortsighted than that which is so widely adopted at the present 

 time by scientific workers of coining special terms to express each new nebulous 

 conception as it arises, whether or no there be real need of such expressions. 



