THE ORIGIN OF SPECIES 165 



The solvency of great mercantile companies rests on the 

 validity of the laws which have been ascertained to govern 

 the seeming irregularity of that human life which the 

 moralist bewails as the most uncertain of things ; plague, 

 pestilence, and famine are admitted, by all but fools, to 

 be the natural result of causes for the most part fully within 

 human control, and not the unavoidable tortures inflicted 

 by wrathful Omnipotence upon His helpless handiwork. 



Harmonious order governing eternally continuous pro- 

 gress the web and woof of matter and force interweaving 

 by slow degrees, without a broken thread, that veil which 

 lies between us and the Infinite that universe which alone 

 we know or can know ; such is the picture which science 

 draws of the world, and in proportion as any part of that 

 picture is in unison with the rest, so may we feel sure 

 that it is rightly painted. Shall Biology alone remain out 

 of harmony with her sister sciences ? 



Such arguments against the hypothesis of the direct 

 creation of species as these are plainly enough deducible 

 from general considerations ; but there are, in addition, 

 phenomena exhibited by species themselves, and yet not 

 so much a part of their very essence as to have required 

 earlier mention, which are in the highest degree perplexing, 

 if we adopt the popularly accepted hypothesis. Such 

 are the facts of distribution in space and in time ; the 

 singular phenomena brought to light by the study of 

 development ; the structural relations of species upon 

 which our systems of classification are founded ; the 

 great doctrines of philosophical anatomy, such as that of 

 homology, or of the community of structural plan exhibited 

 by large groups of species differing very widely in their 

 habits and functions. 



The species of animals which inhabit the sea on opposite 

 sides of the isthmus of Panama are wholly distinct ; * the 

 animals and plants which inhabit islands are commonly 

 distinct from those of the neighbouring mainlands, and 

 yet have a similarity of aspect. The mammals of the 

 latest tertiary epoch in the Old and New Worlds belong 

 to the same genera, or family groups, as those which now 

 inhabit the same great geographical area. The crocodilian 

 reptiles which existed in the earliest secondary epoch were 

 similar in general structure to those now living, but exhibit 



* Recent investigations tend to show that this statement is not 

 strictly accurate. 1870. 



