VARIE1'\ A\D UNITY IX LIFE 



10 



space, for these again bring other events and disclose otlicr 

 barriers. A closer observation will show us that the range of 

 variety is far greater than is indicated by the nunil)or of species. 

 There is not one blade of grass in the meadow exactly like anv 

 other blade. There is not a scpiirrel in the forest like anv 

 other squirrel, not a duck on the ])oiid like any other duck in 

 every detail of its structure. If we compare two rose leaves 

 we shall find differences in size, in serration of the margin, in 

 the length of the stalk, in the hairs 

 on the surface, in the intensit}' of 

 the green, in the number of breath- 

 ing pores on the low^er side. In 

 every structure and function where 

 difference is i:)ossible variation will 

 appear. The squirrels or the ducks 

 will differ in shade of color, in dis- 

 tinctness of marking, in length of 

 limb, in breadth of organ, in every 

 way in which there is play for in- 

 dividualism. 



Nor are these differences limited 

 to matters of color or form. There 

 are like variations in function, in 

 tendency, in disposition, in endur- 

 ance. No tw^o men ever bore the 

 same features, no two ever held the 

 same character, no two ever lived 

 the same life. The traits of the in- 

 dividual, however small, appear on 

 every hand. It is b}^ little traits of 



emphasis that we recognize our friends. The same individu- 

 alism is possessed by the lower animals and by ])lants, though 

 the differences in stress and emphasis in color and figure are 

 most marked in creatures of the most highly sj)ecialized organi- 

 zation. In all animals and all plants like difTerences obtain. 

 No two individuals of any species are ever (juite the same. No 

 two germ cells of the same parent are ever (juite alikiv Xo two 

 cells in the body are ever exactly identical. Among |>lants of 

 the same kind in the field, some are cut down by frost while 

 others persist; some are destroyed by drought while others en- 

 dure; some are immune to attacks of rust while others arc e.v 



FiG. 8. — Sea cucumhfr. Curu- 

 ynaria, sp. (Natural site.) 



