328 THE CAUSES OF THE 



XI 



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, 

 furthermore, 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, recapitu- 

 late 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 

 analysed the present condition of animated nature, 

 until we found that each species took its origin in 

 a form similar to that under which all the others 

 commenced their existence. We have found the 

 whole of the vast array of living forms with which 

 we are surrounded, constantly growing, increasing, 

 decaying and disappearing ; the animal constantly 

 attracting, modifying, and applying to its susten- 

 ance the matter of the vegetable kingdom, which 

 derived its support from the absorption and con- 

 version of inorganic matter. And so constant and 

 universal is this absorption, waste, and repro- 

 duction, that it may be said with perfect certainty 

 that there is left in no one of our bodies at the 



