BIOLOGICAL BEGINNINGS 23 



brain in a human foetus at the end of the seventh month reach about the 

 same stage of development as in a baboon when adult. The great toe, as 

 Prof. Owen remarks, "which forms the fulcrum when standing or walking, 

 is "perhaps the most characteristic peculiarity in the human structure;" but 

 in an embryo, about an inch in length. Prof. Wyman found "that the great 

 toe was shorter than the others; and, instead of being parallel to them, pro- 

 jected at an angle from the side of the foot, thus corresponding with the 

 permanent condition of this part in the quadrumana." I will conclude with 

 a quotation from Huxley, who after asking, does man originate in a dif- 

 ferent way from a dog, bird, frog or fish? says, "the reply is not doubtful 

 for a moment; without question, the mode of origin, and the early stages 

 of the development of man, are identical with those of the animals imme- 

 diately below him in the scale: without a doubt in these respects, he is far 

 nearer to apes than the apes are to the dog." 



RUDIMENTS 



This subject, though not intrinsically more important than the two 

 last, will for several reasons be treated here more fully. Not one of the 

 higher animals can be named which does not bear some part in a rudi- 

 mentary condition; and man forms no exception to the rule. Rudimentary 

 organs must be distinguished from those that are nascent; though in some 

 cases the distinction is not easy. The former are either absolutely useless, 

 such as the mammae of male quadrupeds, or the incisor teeth of ruminants 

 which never cut through the gums; or they are of such slight service to 

 their present possessors, that we can hardly suppose that they were devel- 

 oped under the conditions which now exist. Organs in this latter state are 

 not strictly rudimentary, but they are tending in this direction. Nascent or- 

 gans, on the other hand, though not fully developed, are of high service to 

 their possessors, and are capable of further development. Rudimentary or- 

 gans are eminently variable; and this is partly intelligible, as they are useless, 

 or nearly useless, and consequently are no longer subjected to natural selec- 

 tion. They often become wholly suppressed. When this occurs, they are 

 nevertheless liable to occasional reappearance through reversion — a cir- 

 cumstance well worthy of attention. 



The chief agents in causing organs to become rudimentary seem to have 

 been disuse at that period of life when the organ is chiefly used (and this 

 is generally during maturity), and also inheritance at a corresponding 

 period of life. The term "disuse" does not relate merely to the lessened 

 action of muscles, but includes a diminished flow of blood to a part or or- 

 gan, from being subjected to fewer alternations of pressure, or from be- 

 coming in any way less habitually active. Rudiments, however, may occur 

 in one sex of those parts which are normally present in the other sex; and 

 such rudiments, as we shall hereafter see, have often originated in a way dis- 

 tinct from those here referred to. In some cases, organs have been reduced 



