Chap. XVI. FROM DOMESTICATION. 91 



cated breeds are nearly twice as fertile as dovecots: the latter, 

 however, when caged and highly fed, become equally fertile with 

 house pigeons. I hear from Judge Caton that the wild turkey in 

 the United States does not breed when a year old, as the domesti- 

 cated turkeys there invariably do. The peahen alone of domesti- 

 cated birds is rather more fertile, according to some accounts, when 

 wild in its Dative Indian home, than in Europe when exposed to our 

 much colder climate. 33 



With respect to plants, no one would expect wheat to tiller more, 

 and. each ear to produce more grain, in poor than in rich soil ; or to 

 get in poor soil a heavy crop of peas or beans. Seeds vary so much 

 in number that it is difficult to estimate them ; but on comparing 

 beds of carrots in a nursery garden with wild plants, the former 

 seemed to produce about twice as much seed. Cultivated cabbages 

 yielded thrice as many pocls by measure as wild cabbages from the 

 rocks of South Wales. The excess of berries produced by the culti- 

 vated asparagus in comparison with the wild plant is enormous. 

 No doubt many highly cultivated plants, such as pears, pineapples, 

 bananas, sugar-cane, &c, are nearly or quite sterile; and I am 

 inclined to attribute this sterility to excess of food and to other 

 unnatural conditions ; but to this subject I shall recur. 



In some cases, as with the pig, rabbit, &c, and with those 

 plants which are valued for their seed, the direct selection of 

 the more fertile individuals has probably much increased 

 their fertility; and in all cases this may have occurred in- 

 directly, from the better chance of some of the numerous 

 offspring from the more fertile individuals having been pre- 

 served. But with cats, ferrets, and dogs, and with plants 

 like carrots, cabbages, and asparagus, which are not valued 

 for their prolificacy, selection can have played only a sub- 

 ordinate part ; and their increased fertility must be attributed 

 to the more favourable conditions of life under which they 

 have long existed. 



33 For the eggs of Gallus hanhvn, Pigeons,' p. 158. With respect to 



see Blyth, in 'Annals and Mag. of peacocks, according to Temminck 



Nat. Hist.,' 2nd series, vol. i., 1848, ('Hist. Nat. Gen. des Pigeons,' &c, 



p. 456. For wild and tame ducks, 1813, torn. ii. p. 41), the hen lays in 



Macgillivray, 'British Birds,' vol. v. India even as many as twenty eggs; 



p, 37; and 'Die Enten,' s. 87. For but according to Jerdon and another 



wild geese, L. Llovd, ' Scandinavian writer (quoted in Te^etmeier's 



Adventures,' vol. 'ii. 1854, P. 413; 'Poultry Book,' 1866, pp. 280, 282), 



and for tame geese, ' Ornamental she there lays only from four to nine 



Poultry,' by Rev. E. S. Dixon, p. 139. or ten eggs: in England she is said, 



On the breeding of Pigeons, Pistor, in the ' Poultry Book,' to lay rive or 



'Das Ganze der Taubenzucht,' 1831, six, but another writer says from 



s. 46 ; and Boitard and Corbie ' Les eight to twelve eggs. 



