2 54 BIOLOGICAL LECTURES. 



Bonnet brings forward the phases of development in the 

 chick as helping us to form some idea of the "revolutions" 

 through which organisms are carried by this " natural evolu- 

 tion." The comparison is of interest to us in two ways : 

 First, it shows that Bonnet did not regard the germ as a fac- 

 simile of the adult ; and secondly, it reminds us of the parallel 

 which modern embryology traces between the development of 

 the individual and that of the race — between the ontogenetic 

 and the phylogenetic series. The phases of the chick are first 

 briefly sketched: 



" It is not without astonishment that we behold the strange 

 revolutions which the chick undergoes from the time when it 

 begins to be visible to the time when it shows its true form. 

 I shall not redescribe those revolutions here. It is sufficient 

 to remind the reader that when the chick begins to be visible, 

 it appears under a form which resembles closely that of a very 

 small worm. Its head is large, and to this head is attached a 

 sort of tapering appendage. It is in this appendage, so like 

 the tail of a small worm, that the trunk and limbs of the 

 animal are contained. The whole is extended in a straight 

 line and is motionless. . . . 



..." TJie different successive phases under wJiich the chick 

 shozvs itself, enable ns to form an idea of the different revolutions 

 which organized bodies have to undergo in order to reach this last 

 fonn by which they are known to 21s. . . . 



"All this helps ns to conceive the 7iew forms which animals 

 will take in that future state to which I conjecture they are 

 called. This small organic body, by which their soul is 

 actually bound to the grosser body, incloses already, infinitely 

 small, the elements of all the parts which will compose that 

 new body under which the animal will appear in its future 

 state. 



" The causes which will effect this revolution of our globe, 

 of which the Apostle speaks, will be able at the same time to 

 effect the more or less accelerated development of all the ani- 

 mals concentrated into those organic points which I might 

 call germs of restitution:' {Paling., Part I, Chap. IV, pp. 

 125, 126.) 



