480 LAWS OF MULTIPLICATION. 



greatest inactivity — where there is plenty to eat and nothing 

 to do. There is no less distinct evidence that amonj 



domesticated Mammals themselves, the well-fed individual 

 are more prolific than the ill-fed individuals. On the high 

 and comparatively-infertile Cotswolds, it is unusual for 

 ewes to have twins; but they very commonly have twins 

 in the adjacent rich valley of the Severn. Similarly, among 

 the barren hills of the west of Scotland, two lambs will be 

 borne by about one ewe in twenty; whereas in England, 

 something like one ewe in three will bear two lambs. Nay, 

 in rich pastures, twins are more frequent than single births ; 

 and it occasionally happens that, after a genial autumn and 

 consequent good grazing, a flock of ewes will next spring 

 yield double their number of lambs — the triplets balancing 

 the uniparae. So direct is this relation, that I have heard a 

 farmer assert his ability to foretell, from the high, medium, 

 or low, condition of an ewe in the autumn, whether she will 

 next spring bear two, or one, or none. 



§ 355. An objection must here be met. Many facts may 

 be brought to prove that fatness is not accompanied by ferti- 

 lity but by barrenness ; and the inference drawn is that high 

 feeding is unfavourable to genesis. The premiss may be 

 admitted while the conclusion is denied. 



There is a distinction between what may be called normal 

 plethora, and an abnormal plethora, liable to be confounded 

 with it. The one is a mark of constitutional wealth ; but the 

 other is a mark of constitutional poverty. Normal plethora 

 is a superfluity of materials both for the building up oJ 



and hence, probably, the differences between the statements of different at 

 thorities concerning these several cases. Prof. MacBride writes : — 



"According to Flower (Mammals, Living and Extinct) the Ferret is a 

 domesticated variety of the common polecat, which has 3 to 8 young. Dar- 

 win (Animals and Plants) says that the wild sow often breeds twice a year 

 and produces a litter of 4 to 8, and sometimes even 12. The domestic sow 

 breeds twice and would breed oftener if permitted, and if any good at all pro- 

 duces 8 in litter." 



