DESIGN IN THE ORGANIC WORLD. 431 



the exterior. This cavity is lined by epidermic cells, out of which 

 the crystalline lens is ultimately formed ; the derm on which they 

 rest becomes its capsule ; and the loose tissue which underlies the 

 derm becomes the vitreous humour. The back of the globe thus 

 formed, meeting the pear-shaped projection of the brain, pushes 

 it, as it were, inwards ; and thus derives from it the retinal invest- 

 ment which is necessary to bring the optical apparatus into rela- 

 tion with the nervous centres. Neither of these developmental 

 processes would be of any use without the other. It is only by 

 the conjunction of the two, that this most perfect and elaborate 

 instrument is brought into existence. 



I have now put before you the original Argument from Design, 

 as set forth by Paley, expanded by the more advanced knowledge 

 of the present time. That this argument, based on the combina- 

 tion of adaptations presented in the structure of each organic type 

 — considered as a " special creation " — to the external conditions 

 of its existence, needs now to be reconstructed under the new 

 light of the Evolution-doctrine, must be freely admitted by those 

 who (like myself) maintain it to be still tenable. And I have 

 now to inquire how it is affected, first by the acceptance of the 

 doctrine of Evolution taken per se; and secondly by the explana- 

 tion supposed to be given of that Evolution by attributing it to 

 " Natural Selection." 



I can best bring you to my own mode of viewing this question, 

 by first leading you to consider how it has been affected by the 

 substitution of our present knowledge of the evolution of any one 

 of the higher types from its protoplasmic germ-particle, for the old 

 notion that this germ-particle is a miniature representation of the 

 mature embryo, into which it has only to expand by growth. 

 The primordial "jelly-speck" in the Fowl's egg during the pro- 

 gress of its development into the fully-formed chick, passes 

 through a succession of phases, of which the first represents that 

 lowest or most homogeneous type of organization which is 

 common to the simplest Plants and the simplest Animals, — the 

 second, one which is distinctively Animal, — the third, one which is 

 distinctively Vertebrate, — the fourth, one which is distinctively 

 Oviparous, — and the fifth, one which is distinctively Ornithic, — 



