We are just as much bewildered in respect to this vital principle in our classifications of the myriads of little creatures careering over the field of the microscope, as when we turn to the most marked formations of genera and species in geological distribution. The great trouble with Mr. Darwin's _vinculum_ is, that its weakest links are precisely where the strongest should be found, and _vice versa_. With a candor rarely displayed by a writer who is spinning a theory, he admits this. The geological record is not what he would have it to be. Whole chapters are gone where they are most needed, and nature's lithography seems constantly at fault. Independent species are now and then springing up where derivatives should be looked for, while derivatives are everywhere disappearing in non-derivatives. Many of the middle Tertiary _molusca_, and a large proportion of the later Tertiary period, are specifically identical with the living species, of to-day. What has "natural selection" been doing for this family in the last million years or more? Manifestly nothing, and less than nothing, for some of the species have dropped out altogether. These facts, and hundreds of others like them, are constantly obtruding themselves upon our attention to show, in harmony with the Bible Genesis, the immutability of species--the absolute fixity of types--rather than their variability, as claimed. If nature abhors anything more than a _vacuum_, it is manifestly any marked transition from fixed types, and she thunders her edicts against it in the non-fertility of all hybrids. The doctrine of variation lacks the all-essential element of continuity, and is oftener at war with the theory of the "selection of the fittest," than it is with the selection of the "unfit." The leap from Lepidosirens to Amphibians is no greater than the interval between any two species of animals or plants yet discovered, either fossil or living. The intervals are as numerous as the species themselves, and everywhere constitute great and sudden leaps, or such transitional changes as "natural selection" could not have effected independently of intervening forms--those that nowhere exist in nature, and never have existed, if we are to credit geologic and paleontologic records. There is everywhere similarity of structure, but not identity; and the nearer we approach to identity of structure the wider the divergence in similarity of characteristics. A bird may be taught to talk and sing snatches of music. But no monkey has ever been able to articulate human sounds, much less give them rhythmical utterance.