706 The Outline of Science 



conception, and though the fact of what we may call "blood- 

 relationship" lies behind every so-called natural classification, our 

 present point is simply that orderly classifiability is undeniable. 

 As Goethe said: "Each of her works has an essence of its own; 

 each of her phenomena a special characterisation; and yet their 

 diversity is in unity." 



Abundance and Insurgence of Life 



A second impression is that of wealth of numbers and of 

 indomitable will to live. There are, indeed, organisms which 

 multiply slowly, such as elephants, golden eagles, and century 

 plants, but this is not the way with the majority. Most of the 

 streams of life are ever tending to overflow their banks. Even 

 the rarities may do so in appropriate conditions; thus a rather 

 rare wingless Glacier-Insect was recently found on one stretch 

 of the mer-de-glace at Chamonix, in numbers almost equal to the 

 population of Great Britain and Ireland. In the case of organ- 

 isms of low individuation, which hold their own rather because 

 they are many than because they are strong or wise, the prodi- 

 gality of productivity is beyond all our powers of conception. 

 From one infusorian there may be a million by the end of a 

 week, and in some of the floating meadows of the sea there may 

 be a quarter of a million units in a gallon of water. There is a 

 well-known British starfish, Luidia ciliaris, which produces at 

 least two hundred millions of eggs, and yet it is not what one 

 would call a common animal. 



We are familiar with calculations of what would occur if 

 there were no thinning of the crops how soon the earth would 

 be covered with a weed, or the sea filled solid with a fish, or the 

 sky darkened with an insect, and recurrent plagues or locusts, 

 sparrows, rabbits, and moles remind us that a possibility may 

 easily become an actuality. After allowing a prodigious mor- 

 tality of 95 per cent, it is computed that the 10,000,000 pairs of 

 breeding rats in Great Britain on New Year's Day, 1918, were 



