224 ORGAXS OF EXTREME PERFECTION. [Chap. VI. 



could have been formed by natural selection, seems, I 

 freely confess, absurd in the highest degree. When it 

 was first said that the sun stood still and the world 

 turned round, the common sense of mankind declared 

 the doctrine false ; but the old saying of Vox pojmli, 

 vox Dei, as every philosopher knows, cannot be trusted 

 in science. Eeason tells me. that if numerous gradations 

 from a simple and imperfect eye to one complex and 

 perfect can be shown to exist, each grade being useful 

 to its possessor, as is certainly the case ; if further, the 

 eye ever varies and the variations be inherited, as is 

 likewise certainly the case; and if such variations 

 should be useful to any animal under changing con- 

 ditions of life, then the difficulty of believing that a 

 perfect and complex eye could be formed by natural 

 selection, though insuperable by our imagination, 

 should not be considered as subversive of the theory. 

 How a nerve comes to be sensitive to light, hardly 

 concerns us more than how life itself originated ; but I 

 may remark that, as some of the lowest organisms, in 

 which nerves cannot be detected, are capable of per- 

 ceiving light, it does not seem impossible that certain 

 sensitive elements in their sarcode should become 

 aggregated and developed into nerves, endowed with 

 this special sensibility. 



In searching for the gradations through which an 

 organ in any species has been perfected, we ought to 

 look exclusively to its lineal progenitors ; but this is 

 scarcely ever possible, and we are forced to look to 

 other species and genera of the same group, that is to 

 the collateral descendants from the same parent-form, 

 in order to see what gradations are possible, and for the 

 chance of some gradations having been transmitted in 



