REPORTS OF SOCIETIES. 
813 
The feeble linnet is continually flying about to pick up liis 
spare vegetal diet, thus involving much expenditure. The 
superior strength and intelligence of the blackbird enables it 
to procure a better and more varied diet—grain, fruit, worms, 
snails, beetles, larvae. “ The result is that the blackbird is 
ready to breed very early in spring, and is able during the 
summer to rear a second, and sometimes even a third brood.” 
A comparison illustrating the same principle is instituted 
between the rat and the mouse. Both are equally prolific, 
although they differ greatly in size. But the rat, by its greater 
power, intelligence and cunning, is enabled to get a far larger 
and varied supply of nourishment than the mouse, which is 
mainly a vegetal feeder, without involving extra expenditure ; 
“ and this relative excess of nourishment makes possible alarge 
size without a smaller rate of multiplication.” The same 
principle is further evidenced by the contrast between the 
common rat and the water-rat. The common rat has several 
broods of as many as twelve each in a year, while the water- 
rat, a vegetal feeder, though somewhat smaller, has no more 
than six in a brood, and only one or two broods in a year. 
The difference between them, as in previous cases, is there¬ 
fore mainly owing to the character of their food. 
It is thus demonstrated that the inverse ‘‘variation of 
Individuation and Genesis is, therefore, but approximate,” 
and the general law is seen that “Genesis decreases not 
quite so fast as Individuation increases.” 
Before approaching the final chapters in this grand work, 
on the “ Multiplication of the human race,” and on “ Human 
population in the future,” which are of the most vital impor¬ 
tance and interest, Mr. Spencer sums up the preceding 
evidence in these words :—“ Hence everv tvpe that is best 
adapted to its conditions, which on the average means every 
higher type, has a rate of multiplication that insures a 
tendency to predominate. Survival of the fittest, acting- 
alone, is ever replacing inferior species by superior species. 
But beyond the longer survival, and therefore greater chance 
of leaving offspring, which superiority gives, we see here 
another way in which the spread of the superior is insured. 
Though the more-evolved organism is the less fertile 
absolutely, it is the more fertile relatively.” 
Imports of .Societies. 
BIRMINGHAM NATURAL HISTORY AND MICROSCOPICAL 
SOCIETY. —Sociological Section. Tuesday, October 25th. At this 
the first meeting of the section for the session, the President, Mr. W. 
R. Hughes, F.L.S., delivered a brief address on “ The Progress of the 
