138 DUBLIN NATURAL HISTOKY SOCIETY. 



II. TJiat the causes of variation assigned, viz., cross-breeding (Buf- 

 fon) ; imitation (Lamarck) ; and natural advantage in the struggle for 

 existence (Darwin), are sufficient to account for the effects asserted to be 

 produced. 



III. That succession implies causation. 



On each of these a few words of explanation are necessary. 



I. The indefinite variation of species continuously in the one direction. 

 This has been expressed by some Lamaitkians as a state of unstable 



equilibrium of nature ; but, should we assume the existence of a law, 

 which is contraiy to all we know of every other department of nature? 

 If we must have a mechanical analogy to fix our ideas, nature might be 

 better compared to a condition of dynamic equilibrium, in which all the 

 parts are in motion, and never return to precisely the same relative 

 positions, but, nevertheless, continually balance round certain definite 

 positions of equilibrium, which never change. What should we think 

 of the astronomer, who, from a few years' observation of the precession 

 of the equinoxes, should predict that in due time the north pole of the 

 earth's axis would point to the same position among the stars that the 

 south pole now occupies ? Yet this very species of assumption is made 

 by Lamarck and Darwin, in their appeal to the supposed influence of a 

 long lapse of time. Yet, in the writings of the latter progressionist 

 there is this singular inconsistency, that while he shows the utmost 

 eifects of human breeding on domestic animals to be capable of produc- 

 tion in ten or twenty years, he denies the right of his adversaries to 

 appeal to the unaltered condition of the ass, the ostrich, or the cat, for 

 3000 years, as a proof that specific forms balance round central types, 

 and have no tendency to depart indefinitely from them. 



Is it rational to suppose that man can alter the head and neck of a 

 pigeon into any desired form in six years, and that nature, with her 

 greater skill, cannot in 3000 years lengthen the ostricli's wings by a 

 single inch, although, according to the theory, it is her evident wish to 

 do so ? 



II. The causes of Variation assigned are not adequate to produce the 

 effects assigned to them. — The discussion of the inadequacy of the causes 

 assigned would lead to a treatise longer than that of Bulfon, Lamarck, 

 or Darwin — and I must therefore content myself with an example. 

 The humble bee and the hive bee coexist together, and the latter is 

 supposed to be developed from the former by the law of natural selec- 

 tion, breeding, in succession, bees possessed of the talent of economizing 

 more and more of wax in the construction of their cells. 



1. The humble bee constructs single cells, and uses 100 units of 

 wax. 



2. A bee (not known to science, but, doubtless, extinct) was grown, 

 that made cells in the form oi equilateral triangles placed in double 

 combs, with flat bottoms to the cells. This bee used only 50 units of 

 wax. 



