72 . THE HISTORY OF CREATION. 



wliicli have developed independently of one another and 

 independentl}" of the animal and the vegetable kingxloms. 

 Even if we adopt the monophyletic hypothesis of descent, and 

 maintain a common origin from a single form of Moneron for 

 all organisms, without exception, which ever have lived and 

 still live upon the earth, even in this case the connection 

 of the neutral Protista on the one hand with the vegetable 

 kingdom, and on the other hand with the animal 

 kingdom, must be considered as very vag-ue. We must 

 regard them (compare p. 74) as lower offshoots which have 

 developed directly out of the root of the great double - 

 branched organic pedigTee, or perhaps out of the lowest tribe 

 of Protista, which may be supposed to have shot up midway 

 between the two diverging high and vigorous trunks of the 

 animal and vegetable kingdoms. The individual classes of 

 the Protista, whether they are more closely connected at 

 their roots in groups, or only form a loose bunch of root off- 

 sets, must in this case be regarded as having nothing to do 

 either with the diverging groups of organisms belonging to 

 the animal kingdom on the right, or to the vegetable kingdom 

 on the left. They must be supposed to have retained the 

 original simple character of the common primaeval living 

 thing more than have genuine animals and genuine plants. 



But if we adopt the polyphyletic hypothesis of descent, 

 we have to imagine a number of organic tribes, or phyla, 

 which all shoot up by spontaneous generation out of the 

 same ground, by the side of and independent of one 

 another. (Compare p. 75.) In that case numbers of dif- 

 ferent Monera must have arisen by spontaneous generation 

 whose differences would depend only upon slight, to us 

 imperceptible, differences in their chemical composition, and 



