202 Referate. 



another, while in another case a species may be constant in one locality 

 and variable in another. Intermediates or overlapping forms may exist in 

 intermediate areas, but there is no evidence to show how the local forms 

 diverged, nor, what the parent form was like. In some cases the differences 

 between local races are due to Mendelian factors, but there is no evidence 

 to show why a factor exists in one, and is absent from the other. 



The chapters on Adaptation and the Causes of Variation emphasize 

 our ignorance even more strongly. The evidence adduced for adaptation 

 or mutation by the inheritance of acquired characters whether by direct 

 influence of conditions on the germ or by somatic induction, is criticized 

 in a way which some will regard as unduly severe. But the grounds of 

 criticism are always given, and it is well to remember that an attitude of 

 scepticism towards observations which have as yet no independent con- 

 firmation is much more likely to lead to knowledge than the uncritical 

 acceptance of supposed facts which may be mistaken. The last chapter 

 deals with interspecific sterility, and is in some ways disappointing It 

 gives a lucid exposition of the experimental results, and shows how little 

 we know of the physiological basis of fertility or sterility, but no reference 

 is made to the considerable body of facts which have been accumulated 

 on the cytological side. These, of course, tell us little of the 'why' of 

 sterility, but thev do add considerably to our knowledge of how it is 

 brought about. Taken as a whole, the book is one which every student 

 of genetics should read carefully, not only to impress him with the limi- 

 tations of our present knowledge, but because it indicates in every chapter 

 lines on which advance may be made. L. DONXASTER. 



Castle, W. E., Coulter, J. M., Davenport, C. B., East, E. M., and Tower, W. L. 



Heredity and Eugenics. A course of lectures summarizing recent advances 

 in knowledge of variation, heredity, and evolution and its relation to 

 plant, animal, and human improvement and welfare. University of 

 Chicago Press, igi2. (London: Cambridge University Press.) Price 

 10 sh net. 

 The preface tells us that the lectures published together under the 

 title 'Heredity and Eugenics' were given at Chicago in 1911, and were in 

 tended for a general university audience rather than for those trained in 

 biology. The lectures are ananged as follows: (i) General Introduction, 

 and (2) The physical basis of heredity from the cytological stand point, 

 by Prof. Coulter; (3) The method of evolution, and (4) Heredity and 

 Sex, by Prof. CASTLE; (5) Inheritance in the higher plants and (6) The 

 application of biological principles to plant breeding, by Prof. EAST; 

 (7) Modification of the germinal constitution by experimental processes, 

 by Prof. Tower; (8) Inheritance of physical and mental traits in man 

 and (9) Geography of Man in relation to Eugenics, by Dr DAVENPORT. 

 All the lecturers have written their sections clearly, and the whole 

 book is illustrated with admirable figures, so that the class of readers for 

 whom it is intended will find in it a simple and in general easily comprehen- 

 sible account of the present position of the problems dealt with. The cases 

 chosen are in nearly all cases already well known, so that for the more 

 serious student the book will provide a useful summary, but little that is 

 really new. Many, however, will welcome the fresh presentation of some 

 of the facts in a readily accessible form. In this respect Prof. ToWER's 

 account of his experiments in the production of variation in Chrysomelid 



