SEPTENARY AND OTHER SYSTEMS. 223 



racy. The question is not, how many apparent divi- 

 sions can be made? but does each division, by itself, 

 form a circular group ? If not, they cannot be natural. 

 If such writers would only recollect the admission which 

 they set out with, that every natural group is a circle, 

 " they would not so often flounder about in all the 

 difficulties which necessarily attend the supposition of 

 two determinate numbers." * 



(273.) Mr. MacLeay makes the following sound ob- 

 servations regarding septenary theories ; and they are 

 equally applicable to any determinate number which spe- 

 culative ideas may give rise to. " The number seven 

 might also, perhaps, for obvious reasons, occurtothemind, 

 were it allowable in natural history to ground any rea- 

 soning except upon facts of organisation. The idea 

 of this number is, however, immediately laid aside, on 

 endeavouring to discover seven primary divisions of 

 equal degree in the animal kingdom. It is easy, indeed, 

 to imagine the prevalence of a number; the difficulty 

 is to prove it. The naturalist, therefore, requires 

 something more than the statement of a number, before 

 he allows either a preconceived opinion, or any analogy 

 not founded on organic structure, to have an influence 

 on his favourite science. He requires its application to 

 nature, and its illustration by facts." t 



* MacLeay's Letter to Dr. Fleming, p. 33. 

 ■)■ Linn. Trans, vol. xiv. p. 57. note. 



