DESIGN IN THE ORGANIC WORLD. 427 



centrated upon the thing at which we specially wish to look, the 

 more distinctly we see it. The Microscopist well knows the great 

 advantage of limiting his field of view when he is examining 

 objects of the greatest difficulty. And every one who has been 

 accustomed to visit picture-galleries is aware how much more fully 

 he is able to appreciate a picture, when he looks at it in such a 

 manner that its surroundings are kept out of his view. 



To be able to bring our fullest measure of visual power to bear 

 upon any object we desire to examine, and at the same time to 

 see surrounding objects with sufficient distinctness for the recog- 

 nition of their local relation to it, is, thus, far more advantageous 

 to us, than would be the extension of that highest degree of visual 

 power over the whole range at once. Here again, therefore, the 

 asserted imperfection of the eye as an optical instrument proves 

 to be the very contrary, when its structure and action are regarded 

 in their relations to the use we make of the organ ; added force 

 being thus given to the final conclusion drawn by Professor Helm- 

 holtz, that " the adaptation of the eye to its function is most com- 

 " plete, and is seen in the very limits which are set in its defects " 

 (p. 228). — Those who quote his previous statement for the purpose 

 of depreciating the perfection of the organ, are bound in honesty 

 to cite this also. 



In the human eye, then, as in the Walter printing-machine, we 

 find a combination of a number of separate contrivances, each 

 individually of the most elaborate kind, yet having most complete 

 consentaneousness of action, all tending towards one common end, 

 which is attained with a perfection not theoretically surpassable 

 by our highest science. And the cumulative probability that the 

 eye, like the machine, is the product of " intelligent design," though 

 not logically demonstrative, has a cogency not inferior to the 

 " moral certainties " on which we are accustomed to rely in the 

 ordinary conduct of our lives. — This argument seems to me not to 

 be in the least invalidated, but rather to be strengthened, by the 

 fact that in the ascending series of animals we meet with eyes 

 which, compared with ours, are very imperfect. Beginning at the 

 bottom, we find a little coloured spot, generally on some part of 

 the surface of the animal, with a nerve-fibre proceeding from the 

 central ganglion to that spot ; and we judge this to be a rudimental 

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