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THE AMERICAN NATURALIST. [Vol. XXXV 11 1. 



orthogenesis. In this breadth of view Plate doubtless approaches 

 nearer to the spirit of the great master than the Neo-Darwinians. 

 Nevertheless, in so far as a criticism may be aimed at the book it 

 concerns Plate's unwillingness to accept more freely some of the 

 other subsidiary or alternative theories that have been proposed. 



of the mutation theory ; and in his discussion of means of isolation 

 he entirely fails to mention Mendel's law of the segregation of 

 parental qualities in the germ cells of mongrels. Nevertheless, this 

 law must be an important factor in preventing the swamping of 

 mutations. In his account of the different theories to explain organic 

 adaptation there is not included the theory proposed by the reviewer 

 and later by T. H. Morgan that there has been a selection by the 

 organism of the environment for which its structure is fitted — but as 

 the preface date is antecedent to the appearance of that theory such 

 conclusion could hardly be expected. 



This brief review can give no adequate idea of the scope, sound- 

 ness and helpfulness of the book. It is recommended to biologists 

 as by far the best on the subject. 



C. B. D. 



Experiments in Heredity. i— Stimulated by the rediscovery of 

 Mendel's Law of crossing, Bateson and Saunders have thrown 

 together the results of their studies on crossing plants and poultry. 

 As this is the first extensive post-Mendelian account of hybridization 

 experiments in animals it may fairly be called epoch-making. 



Miss Saunders worked with two hairy species of Lychnis and also 

 a glabrous variety ; with two varieties of Atropa ; two species, each 

 with two varieties, of Datura ; and various races of Matthiola. In 

 the first cross the hairy character is dominant and the glabrous 

 recessive, as shown by the fact that all the first crosses were hairy. 

 In the second generation, however, both dominant and recessive 

 forms appeared in Mendelian proportions. 



The Atropa experiments were less complete, but appeared to be 

 Mendelian, showing dominance in the first color of the type form. 

 The Datura experiments, involving 12 characters, were much more 

 complex. Also there were exceptions to Mendelism in some cases, 

 although striking adherence to it in others. Finally, the Matthiola 

 experiments were based on so many races mixed together that the 



' Bateson, W. and Miss E. R. Saunders. Report I to the Evolution Committee, 

 Royal Society^ London: Harrison & Sons, St. Martin's Lane, 1902. 160 pp. 



