70 The Scottish Naturalist. 



There are other manifestations of a polar arrangement of 

 phenomena in organic nature. The force that developes the 

 two organic kingdoms as a whole, operates, after a sort in a polar 

 manner. Thus the vegetable kingdom does not pass over at 

 the point of its highest development into the animal, so as to 

 present continuity of rise from the lowest vegetable to the 

 highest animal. Quite the reverse. Both the vegetable and 

 the animal series setting out from a point at which development 

 is at a minimum, and where the two are all but, or altogether, 

 confounded, graduate therefrom in opposite directions, diverg- 

 ing as they ascend each in the scale of organisation in its own 

 sphere, till they reach their respective goals of perfection at the 

 farthest possible remove from each other. The highest plants, 

 not the lowest, are the farthest separated from the highest 

 animals. The two kingdoms culminate at opposite poles. It 

 was Fries, the Swedish botanist that introduced the idea and 

 the term "polarity" into biological science. And this, I 

 believe, was one of his instances. It was Ed. Forbes who first, 

 and I may say, last, suggested the same relation as a generali- 

 sation of palaeontological facts. Arranging the geological 

 formations into two great groups, the Palaeozoic and the Neo- 

 zoic, he found the following contrast between the two, — "The 

 maximum development of genuine types during the Palaeozoic 

 period was during its earlier epochs ; that during the Neozoic 

 periods, towards its later epochs." Such are his words. If in 

 this he has hit on a true reading of the facts, that supreme two- 

 fold division of the formations, Palaeozoic and Neozoic, would 

 be established on the ground of numerical as well as structural 

 relations between the respective organic types of the two series, 

 that is to say, on variation in the intensity of the -force diversi- 

 fying organic forms, as well as on the variety of its products. 



Before proceeding to inquire into the truth of such a theory 

 as this, one is almost tempted to put the question, is it pro- 

 posed in sober earnest ? Or, taking it to have been held 

 seriously (and of that there was never a doubt,) is it not, 

 especially when looked at in view of the author's well known 

 scientific proclivities, of a character to suggest that there may be 

 more of theorising enthusiasm to be expected in it, than either of 

 sober investigation or of inductive truth? " Forbes," says his 

 biographer ; " had a love for broad and often poetic generalisa.- 



