In such creatures we see that, from time to time, one of the segments of the body gradually becomes modified till it assumes the condition of a head, and this remarkable phenomenon is repeated again and again, the body of the worm thus multiplying serially into new individuals which successively detach themselves from the older portion. The development of such a mode of reproduction by "Natural Selection" seems not less inexplicable than does its continued performance through the aid of {212} "pangenesis." For how can gemmules attach themselves to others to which they do not normally or generally succeed? Scarcely less difficult to understand is the process of the stomach-carrying-off mode of metamorphosis before spoken of as existing in the Echinoderms. Next, as to certain patent and notorious facts: On the hypothesis of pangenesis, no creature can develop an organ unless it possesses the component gemmules which serve for its formation. No creature can possess such gemmules unless it inherits them from its parents, grandparents, or its less remote ancestors. Now, the Jews are remarkably scrupulous as to marriage, and rarely contract such a union with individuals not of their own race. This practice has gone on for thousands of years, and similarly also for thousands of years the rite of circumcision has been unfailingly and carefully performed. If then the hypothesis of pangenesis is well founded, that rite ought to be now absolutely or nearly superfluous from the necessarily continuous absence of certain gemmules through so many centuries and so many generations. Yet it is not at all so, and this fact seems to amount almost to an experimental demonstration that the hypothesis of pangenesis is an insufficient explanation of individual evolution. Two exceedingly good criticisms of Mr. Darwin's hypothesis have appeared. One of these is by Mr. G. H. Lewes,[221] the other by Professor Delpino of Florence.[222] The latter gentleman gives a report of an observation made by him upon a certain plant, which observation adds force to what has just been said about the Jewish race. He says:[223] "If we examine and compare the numerous species of the genus _Salvia_, commencing with _Salvia officinalis_, which may pass as the main state of the genus, and {213} concluding with _Salvia verticillata_, which may be taken as the most highly developed form, and as the most distant from the type, we observe a singular phenomenon. The lower cell of each of the two fertile anthers, which is much reduced and different from the superior even in _Salvia officinalis_, is transmuted in other _salviae_ into an organ (nectarotheca) having a very different form and function, and finally disappears entirely in _Salvia verticillata_.