RECENT ADVANCES IN SCIENCE 295 



behaviour, but apparently no sex differences. A certain 

 amount of resemblance is noticeable amongst individuals of 

 the same litter, and considerable difference among different 

 strains. Castle (June 1916) throws " New Light on Blending 

 and Mendelian Inheritance " and deduces that the whole 

 population will gradually resolve itself into relatively constant 

 self-fertilising lines. But because of the slow but continuous 

 blending which occurs, these pure lines will in a few generations 

 form a complete gradation of forms connecting one parental 

 mode with another. In the course of a series of breeding 

 experiments, Little has to record " The Occurrence of Three 

 Recognised Colour Mutations in Mice " (June 19 16). It is 

 the mutation from a grey-bellied agouti pattern to a white- 

 bellied agouti. Firstly it arose independently three times in 

 a hybrid race of mice in which there had been no selection in 

 the direction of the mutation. Secondly it arose once in an 

 inbred race, and in exactly the opposite direction from that in 

 which selection was being made. Another mutation involving 

 the disappearance of the black-producing factor arose in a stock 

 of inbred wild mice, causing the appearance of agouti young. 

 This race was related to the hybrid race in which the white- 

 bellied agouti appeared three times, and it is suggested that this 

 germinal instability may have been introduced by a male 

 ancestor of both races. 



ANTHROPOLOGY. By A. G. Thacker, A.R.C.Sc. 

 The American Anthropologist for October to December 191 5 

 (vol. xvii. No. 4) maintains the high standard of excellence 

 usually reached by this periodical. An admirable characteristic 

 of this magazine is that it habitually caters for every class of 

 reader. Some of the contributions are so very popular and so 

 simply written that the ordinary newspaper-reader, making no 

 pretence of anthropological knowledge, could peruse them with 

 interest and profit, whilst other articles go so deeply into special 

 problems that professed students of those problems may find 

 in the essays new thoughts and original suggestions. The 

 editors of the American Anthropologist are doing most valuable 

 work for their science. In the category of popular articles in 

 this number is an essay by G. Grant MacCurdy of Yale entitled 

 " Race in the Pacific Area, with special reference to the origin 

 of the American Indians : Antiquity of Occupation," The 



