500 SCIENCE PROGRESS 



non-Euclidean Geometry, etc., and on many points the author is misled and 

 misleading. It seems a pity that he should thus throw discredit on the 

 many sound statements contained in his book by a habit which Bacon 

 described as mater errorum et scientiarum omnium calamitas. 



Nevertheless, the capacity for generalising while keeping in close contact 

 with particulars is one of the marks of genius {e.g. Newton, Darwin, and 

 perhaps Einstein). A great scientific or philosophic generalisation is an 

 instrument for production or ideal co-ordination. Dr. Johnstone appears 

 to have a capacity for appreciating generalities, has a considerable know- 

 ledge of exact scientific data, and might produce an instrument of value, if 

 he follows the advice of Goethe, to confine himself and not to try flying in 

 several directions simultaneously. 



R. A. P. RODGERS. 



Hormones and Heredity. A Discussion of the Evolution of Adaptations and 

 the Evolution of Species. By J. T. Cunningham, M.A., F.Z.S. 

 [Pp. XX + 246, with 3 plates.] (London: Constable & Co. Price 245.) 



Prof. J. T. Cunningham is always interesting and stimulating even when 

 we cannot agree with him. In this volume the author has wisely taken the 

 precaution of publishing his original views on the supposed part taken by the 

 internal secretions in heredity. It is a pity that that author's views should 

 have been hidden away for so long, as he says himself, in one paper in a 

 German periodical, and a chapter in an elementary textbook. 



In the first part of this book Mr. Cunningham goes over the historical 

 ground, and in later chapters he develops his theory so far as it concerns 

 somatic sex-characters and certain non-sexual characters. 



We think that the author hangs too much on his " hormone peg " : we 

 like the peg very much, but it will only bear a certain amount, and when he 

 asks us to believe that the horns of animals arose by the irritation produced 

 by generations of buttings, it seems difficult to credit that internal secretions 

 alone can have been concerned. 



With regard to his valuable discussion on Mammalian Sexual Characters, 

 he states that " Marshall himself examined sections of the corpus luteum of 

 Ornithorhynchus and saw much hypertrophied and apparently fully devel- 

 oped luteal cells, but no trace of any ingrowth from the wall of the follicle." 

 Marshall is wrong here, for there is ingrowth in the platypus corpus luteum. 



The author enters into some of the most difficult questions in the evolution- 

 ary theory : everywhere his work is interesting and worth reading. He tells 

 us of many experiments, hitherto unpublished, which he has made. We 

 trust that he will carry the unsuccessful ones to fruition. 



We have no hesitation in saying that the author's book should be read by 

 all who are interested in heredity and sex. 



J. Bronte Gatenby. 



Heredity in the Light o£ Recent Research. By the late L. Donc aster, 

 Sc.D., F.R.S. Third Edition, revised. [Pp. vii + 161.] (Cambridge 

 University Press. Price 4s.) 



This useful little book by the late Prof. Doncaster will again be welcomed, 

 because it has been revised especially in the light of the many recent researches 

 on Mendelism, Heredity in Man, Sex, and especially in view of Prof. 

 Morgan's important contributions, for which a special Appendix has been 

 introduced. This book is written in such a way as to be useful for both the 

 student and the intelligent layman. 



J. Bronte Gatenby. 



