The Section of the "Big Tree" in the Museum 



The uppermost series of cards represents events in General History ; 



The light cards immediately below represent changes of thought in the Philosophy of 



Biology ; 

 The small black cards mark the succession ot centuries in the life of the tree ; 

 Of the cards below the black, 



The first row indicates the advance of General Biology ; 



The second, that of Comparative Anatomy ; 



The third (one card), the discoveries of Palaeontology ; 



The fourth, the progress of Embryology. 



