220 



The Journal of Heredity 



sides. The color of the variegated 

 leaves is very light green, very different 

 from the color of the ordinary leaves, so 

 much so in fact that it can be easily dis- 

 tinguished by even the most casvtal ob- 

 server. The \'ariegated leaves usually 

 have a narrow margin of white or silver 

 color around or nearly around the entire 

 leaf. Irregular areas or stripes of white 

 or silver color visually mark the upper 

 surface of the remainder of the varie- 

 gated leaf area, while the vmder surface 

 is usually of a more uniform color. 



The stems of the variegated branches 

 are of a silver color in contrast with the 

 uniform green of the ordinary stems. 



I have found green branches fre- 

 quently occurring in variegated shrubs, 

 and variegated branches in green shrubs. 



A propagator of Riverside informs me 

 that he has rejjeatedly propagated both 

 varieties from bud variations through 

 the selection of cuttings. In this way, 

 he has isolated the variegated form from 

 the green one, and the green form from 

 the variegated. 



This case is presented as an instance 

 of the origin of a valuable cultivated 

 variety of plants through the i^ropaga- 

 tion of bud variations. It is probable 

 that some of the other \'arieties, if not 

 all, of E. japoniciis have been developed 

 from bud variations. 



It is also a good illustration of the 

 fact that a bud variation rarely affects 

 one character of the plant alone; it fre- 

 quently produces changes in many 

 different characters simultaneouslv. 



A Valuable Text-Book of Animal Breeding 



THE BREEDING OF ANIMALS, by 

 F. B. Mumford, dean of the ccjllcge of agricul- 

 ture ^nd director of the experiment station of 

 the University of Missouri. Pp. 310, price 

 $1.75. New York, The Macmillan Co., 66 

 Fifth Avenue, 1917. (Rural Text-book Series, 

 L. H. Bailey, Editor.) 



Most of the questions which a live- 

 stock breeder asks are answered in 

 Dean Mumford's book, which can be 

 cordially recommended. Reproduction, 

 inheritance, and development all receive 

 full discussion, illustrated with niuner- 

 ous examjiles, and with the omission of 

 most of the unnecessary technicalities. 

 Of course, neither this book nor any 



other will teach a man how to become a 

 successful breeder; that art can be 

 learned only by practice. Professor 

 Miunford's chapter on "The Practice of 

 Breeding" is perhaps not quite up to the 

 standard o'' the rest of the book, but it 

 is really difficult to say anything on that 

 subject, which will be of value for 

 immediate application. On the whole, 

 however, his book gives the facts which 

 the breeder, whether a novice or an old 

 hand, wants to know, and it is marked 

 by sound judgment. The errors no- 

 ticed are few and of minor import- 

 ance. 



Ten per cent of 

 American men of science are unmarried, 

 according to J. McKenn Cattell, who 

 has studied the histories of 1,000 of 

 them (The Scientific Monthly, March, 

 1917). Considering their ages, a scien- 

 tific man is more Hkely to be married 



Families of American Men of Science 



the well-known than a man taken at random from the 

 community. At the average age of 

 29.5 years, they married wives aged on 

 the average, 26 6 years. The American 

 men of science ha\'e on the a\'erage 

 seven- tenths of an adult son, each. 

 Family limitation is much ])ractisc(l. 



The Number of Chromosomes in Man 



The exact number of chromosomes in 

 the germ-cells of man has long been in 

 doubt. H. L. Wieman of the Univer- 

 sity of Cincinnati reports, in the 

 American Journal of Anatomy (January, 

 1917), a study which convinces him 



that the reduced number is twelve, one 

 of which is the sex-chromosome. The 

 number is the same in both negro and 

 white races, he finds — previous work 

 had led to the belief that the negro had 

 twice as manv as the white. 



