Lect. I.] METAMORPHOSIS OF THE FROG. 19 



How does all this bear on mammalian descent? 

 Mammalia are not insects. 



My answer to this curt but pertinent question is— that 

 insects show us what is possible as to metamorphosis 

 in a very high group of the Metazoa, or creatures that 

 change their form during their development. Now, as 

 I have spent the spring and summer, and some part of 

 the grey autumn of my life in observing the phenomena 

 of metamorphosis in the Vertebrata, you will, I hope, of 

 your clemency, listen to my words. 



Before Darwin's Origin of Species had for any length 

 of time been printed and discussed, I had seen such 

 things in the metamorphosis of the common Frog as 

 seemed to me dike the writing in a newly-opened scroll 

 of science. Starting as one of the lowest and most 

 generalised kinds of fish, this creature does not end his 

 strange, eventful history until he has given us the type 

 and promise of almost everything in the structure of a 

 high mammal (or Eutherian), even of Man himself, who 

 lifts himself up above his mammalian fellows. 



Long before our era a gifted captive Jew saw, among 

 the celestial hierarchies that appeared to him in vision, 

 " the likeness as the appearance of a man." To us it is 

 given to see man's image down among the living creatures 

 that crowd around the foot of Jacob's ladder. Bacon 

 remarks that — "Light doth stream down more clearly and 

 divinely into the mind of a young than of an old man, 

 for it is written — ' Your old men shall dream dreams,' 



