350 IN STARRY REALMS. 



I need not multiply illustrations ; the innumerable variety 

 of roses and of geraniums, of apples, and of other fruits, 

 will show how universal is the law of variety among all 

 the productions of the organic world. 



The great doctrine of Natural Selection is founded upon 

 this susceptibility to variation. Suppose that you wished 

 to improve the peas in your garden, it is quite possible to 

 do so in a few years in the following manner : Take 100 

 peas, sow them and preserve the seed. You will have 

 some thousands of seeds, but no two peas will be exactly 

 alike ; pick out the hundred heaviest seeds and sow them 

 again next season. You will have a crop of thousands, 

 from which you are again to pick out the heaviest hun- 

 dred. As this process is repeated year by year you will 

 find that within certain limits the peas are gradually 

 increased in size from one generation to another, and thus 

 it is that improved varieties can be artificially established. 

 The success of this process depends merely upon taking 

 judicious advantage of the variability inherent in the 

 organic world. This we may call an artificial selection as 

 opposed to the natural selection. 



What we have here described as being produced artifi- 

 cially in the pea is going on everywhere on the grandest 

 scale in nature. Take an illustration this time from 

 animal life ; and I choose, as one of the most widely 

 known instances, some incidents in the history of the 

 common herring, which exists in such countless myriads 

 in our oceans. Those who frequent the sea are well 

 acquainted with certain features in the life of the herring. 

 The herring is a fish deservedly prized for food, but it is 

 not only mankind that are fond of devouring it ; 



