The eighth and last stands as follows:—­

     “8.  The developmental theory of Darwin is not needed to enable us
     to understand the regular harmonious progress of the complete
     series of organic forms from the simpler to the more perfect.

“The existence of general laws of Nature explains this harmony, even if we assume that all beings have arisen separately and independent of one another.  Darwin forgets that inorganic nature, in which there can be no thought of a genetic connexion of forms, exhibits the same regular plan, the same harmony, as the organic world; and that, to cite only one example, there is as much a natural system of minerals as of plants and animals.”

We do not feel quite sure that we seize Professor Koelliker’s meaning here, but he appears to suggest that the observation of the general order and harmony which pervade inorganic nature, would lead us to anticipate a similar order and harmony in the organic world.  And this is no doubt true, but it by no means follows that the particular order and harmony observed among them should be that which we see.  Surely the stripes of dun horses, and the teeth of the foetal Balaena, are not explained by the “existence of general laws of Nature.”  Mr. Darwin endeavours to explain the exact order of organic nature which exists; not the mere fact that there is some order.

And with regard to the existence of a natural system of minerals; the obvious reply is that there may be a natural classification of any objects—­of stones on a sea-beach, or of works of art; a natural classification being simply an assemblage of objects in groups, so as to express their most important and fundamental resemblances and differences.  No doubt Mr. Darwin believes that those resemblances and differences upon which our natural systems or classifications of animals and plants are based, are resemblances and differences which have been produced genetically, but we can discover no reason for supposing that he denies the existence of natural classifications of other kinds.

And, after all, is it quite so certain that a genetic relation may not underlie the classification of minerals?  The inorganic world has not always been what we see it.  It has certainly had its metamorphoses, and, very probably, a long “Entwickelungsgeschichte” out of a nebular blastema.  Who knows how far that amount of likeness among sets of minerals, in virtue of which they are now grouped into families and orders, may not be the expression of the common conditions to which that particular patch of nebulous fog, which may have been constituted by their atoms, and of which they may be, in the strictest sense, the descendants, was subjected?

It will be obvious from what has preceded, that we do not agree with Professor Koelliker in thinking the objections which he brings forward so weighty as to be fatal to Darwin’s view.  But even if the case were otherwise, we should be unable to accept the “Theory of Heterogeneous Generation” which is offered as a substitute.  That theory is thus stated:—­