OF ORGANIC NATURE. 27 



dom which has been guessed at and fancied for many 

 years ; but which it has been left to the present time 

 to be demonstrated by the careful study of develop- 

 ment. But is it possible to go another step further 

 still, and to show that in the same way the whole of 

 the organic world is reducible to one primitive con- 

 dition of form ? Is there among the plants the same 

 primitive form of organization, and is that identical 

 with that of the animal kingdom ? The reply to that 

 question, too, is not uncertain or doubtful. It is now 

 proved that every plant begins its existence under the 

 same form ; that is to say, in that of a cell — a particle 

 of introgenous matter having substantially the same 

 conditions. So that if you trace back the oak to its 

 first germ, or a man, or a horse, or lobster, or oyster, 

 or any other animal you choose to name, you shall find 

 each and all of these commencing their existence in 

 forms essentially similar to each other : and, further- 

 more, that the first processes of growth, and many of 

 the subsequent modifications, are essentially the same 

 in principle in almost all. 



In conclusion, let me, in a few words, recapitulate 

 the positions -which I have laid down. And you must 

 understand that I have not been talking mere theory ; 

 I have been speaking of matters which are as plainly 

 demonstrable as the commonest propositions of Euclid 

 —of facts that must form the basis of all speculations 

 and beliefs in Biological science. We have gradually 

 traced down all organic forms, or, in other words, we 

 have analyzed the present condition of animated na- 

 ture, until we found that each species took -its origin in 

 a form similar to that under which all the others com- 

 mence their existence. We have found the whole of 



