Chap. XX. METHODICAL SELECTION. 183 



and out of fifty-seven pens lately (1860) exhibited at the 

 Crystal Palace, all had beards. So it has been in many other 

 cases. But in all cases the judges order only what is occa- 

 sionally produced and what can be improved and rendered 

 constant by selection. The steady increase in weight during 

 the last few years in our fowls, turkeys, ducks, and geese is 

 notorious ; " six-pound ducks are now common, whereas four 

 pounds was formerly the average." As the* time required to 

 make a change has not often been recorded, it may be 

 worth mentioning that it took Mr. Wicking thirteen years 

 to put a clean white head on an almond tumbler's body, 

 " a triumph," says another fancier, " of which he may be 

 justly proud." 20 . 



Mr. Toilet, of Betley Hall, selected cows, and especially 

 bulls, descended from good milkers, for the sole purpose of 

 improving his cattle for the production of cheese ; he steadily 

 tested the milk with the lactometer, and in eight years he 

 increased, as I was informed by him, the product in propor- 

 tion of four to three. Here is a curious case 21 of steady but 

 slow progress, with the end not as yet fully attained : in 

 1784 a race of silkworms was introduced into France, in 

 which one hundred in the thousand failed to produce white 

 cocoons; but now after careful selection during sixty-five 

 generations, the proportion of yellow cocoons has been 

 reduced to thirty -five in the thousand. 



With plants selection has been followed with the same 

 good result as with animals. But the process is simpler, 

 for plants in the great majority of cases bear both sexes. 

 Nevertheless, with most kinds it is necessary to take as much 

 care to prevent crosses as with animals or unisexual plants ; 

 but with some plants, such as peas, this care is not necessary. 

 With all improved plants, excepting of course those which 

 are propagated by buds, cuttings. &c, it is almost indispen- 

 sable to examine the seedlings and destroy those which 

 depart from the proper type. This is called " roguing," and 

 is, in fact, a form of selection, like the rejection of inferior 

 animals. Experienced horticulturists and agriculturists 



20 'Poultry Chronicle,' vol. ii., 21 Isid. Geoffroy St.-Hilaire, ' Hist 



1855, p. 596. Nat. Gen.,' torn. iii. p. 254. 



