THE BAY OF BISCAY. 241 



the apposition of their constituent molecules. Hip- 

 pocrates, with his penetrating genius, gave a clear 

 enunciation of these views when, in speaking of the 

 formation of man, he compared the embryo to a tree, 

 and the different members or viscera to the branches 

 and stems which are successively added, to the trunk. 

 In this doctrine every birth is to a certain degree a 

 creation, and every new individual is truly a product 

 of the individual by whom it has been generated. 



Many naturalists have maintained that the future 

 embryo may be traced solely to the male, and is prima- 

 rily an organic corpuscle (in the case of animals), or a 

 grain of pollen (in the case of vegetables), which pene- 

 trates into the ovum or ovule of the animal or the plant, 

 and here becomes developed as in a kind of nidus.* 

 According to these, the female is entirely passive, 

 and is merely a kind of animated hatching machine, 

 somewhat more perfect perhaps than the ovens of the 

 Egyptians or our own model Eccaleobions. 



* These views have never had many adherents among zoologists, 



and although attempts have been made to reproduce them in the pre- 

 sent day it is not probable that they will meet with greater success. 

 The mass of facts and of precise observations that may be opposed 

 to them is too great, to be set aside by a few exceptional cases that 

 have been observed in the eggs of a very small number of animals. 

 The case is different, however, in respect to botany. Schleiden, one 

 of the most celebrated German botanists, has exhibited considerable 

 talent in developing the doctrine to which we refer, and his theory 

 has been almost universally adopted in his own country. French 

 botanists, after remaining doubtful for a time, are now tolerably 

 well agreed in opposing these views, chiefly in consequence of some 

 most conclusive observations which are more especially due to 

 M. Tulasne, who mainly owes his recent introduction to the 

 Academy of Sciences to his able researches on this difficult subject. 

 VOL. 11. i: 



