ZOOLOGY. 



POLARITY IN THE GEOLOGICAL DISTRIBUTION OF GENERA 



AND ITS CAUSE. 



/ Continued from p. 73. J 



By the Rev, J. WARDROP. 



PHE objection moves the question from its proper point of 

 view. Polarity professes to start from actually ascer- 

 tained facts. The objection abandoning this, the only ground 

 on which the theory can be either established or controverted, 

 meets the inference, which it affirms, with an obstruction drawn 

 from the contingencies of future discovery. Now, polarity does 

 not assume a knowledge of palseontological facts complete in 

 extent. It assumes only a representative completeness — a com- 

 pleteness in kind. And who is entitled to say that the facts 

 known give not a specimen of the true relations of the whole? 

 Since, too, the generalisation deals with the amount, not of in- 

 dividual life, but of generic life, is there not something in that 

 that gives the facts a higher chance of being truly representa- 

 tive ? Then again it is not the part of inductive reasoning to 

 be either solicited to a conclusion or deterred from it by any 

 surmised testimony of the unknown, or any anticipated revela- 

 tion of the future. It only seeks, what with a true instinct 

 polarity seeks, to give to the facts which are actually submitted 

 to its treatment, their full interpretation. In any path of 

 investigation, the facts known, however few they may be, are not 

 scientifically exhausted till all the general views they can 

 suggest, all the laws and theories they can, as they stand, 

 legitimately warrant, are brought to their interpretation. As 

 we must not too readily or too far presume on the unknown, so 

 neither must we at all ignore the known. And if polarity 

 or aught else be a competent rendering of the facts already 



