144 REVIEWS. 



an impulse to the philosopliical investigation of the most backward 

 and obscure branch of the biological sciences of his day ; he has laid 

 the foundations of a great edifice ; but he need not be surprised, if. 

 in the progress of erection, the superstructure is altered by his suc- 

 cessors, like the Duomo of Milan from the Roman to a different 

 style of architecture." 



Entertaining ourselves the opinion that something more 

 than natural selection is requisite to account for the orderly 

 production and succession of species, we offer two incidental 

 remarks upon the above extract. 



First, we find in it — in the phrase " Natural Selection, or 

 a process of variation from external influences " — an example 

 of the very common confusion of two distinct things, namely, 

 variation and natural selection. The former has never yet 

 been shown to have its cause in " external influences," nor to 

 occur at random. As we have elsewhere insisted, if not inex- 

 plicable, it has never been explained ; all we can yet say is, 

 that plants and animals are prone to vary, and that some con- 

 ditions favor variation. Perhaps in this Dr. Falconer may 

 yet find what he seeks : for " it is difficult to believe that 

 there is not in [its] nature, a deeper-seated and innate prin- 

 ciple, to the operation of which Natural Selection is merely an 

 adjunct." The latter, which is the ensemble of the external 

 influences, including the competition of the individuals them- 

 selves, picks out certain variations as they arise, but in no 

 proper sense can be said to originate them. 



Secondly, although we are not quite sure how Dr. Falconer 

 intends to a])ply the law of phyllotaxis to illustrate his idea, 

 we fancy that a pertinent illustration may be dra\A'n from it, 

 in this way. There are two species of phyllotaxis, perfectly 

 distinct, and, we sui)pose, not mathematically reducible the 

 one to the other, — namely, 1, that of alternate leaves, with 

 its varieties ; and 2, that of verticillate leaves, of which 

 opposite leaves })resent the simplest case. That, although 

 generally constant, a change from one variety of alternate 

 phyllotaxis to another should occur on the same axis, or on 

 successive axes, is not surprising, the different sorts being 

 terms of a regular series, — although indeed we have not the 



