1 beneficial variations, whether in body or mind, being preserved, and injurious ones eliminated. Do the races or species of men, whichever term may be applied, encroach on and replace one another, so that some finally become extinct? We shall see that all these questions, as indeed is obvious in respect to most of them, must be answered in the affirmative, in the same manner as with the lower animals. But the several considerations just referred to may be conveniently deferred for a time: and we will first see how far the bodily structure of man shows traces, more or less plain, of his descent from some lower form. In succeeding chapters the mental powers of man, in comparison with those of the lower animals, will be considered. The Bolily Structure of Man.-It is notorious that man is constructed on the same general type or model as other mammals. All the bones in his skeleton can be compared with corresponding bones in a monkey, bat, or seal. So it is with his muscles, nerves, blood-vessels and internal viscera. The brain, the most important of all the organs, follows the same law, as shewn by Huxley and other anatomists. Bischoff, who is a hostile witness, admits that every chief fissure and fold in the brain of man has its analogy in that of the orang; but he adds that at no period of development do their brains perfectly agree; nor could perfect agreement be expected, for otherwise their mental powers would have been the same. Vulpian 2 remarks: “Les différences réelles qui existent entre l'encéphale de "l'homme et celui des singes supérieurs, sont bien minimes. Il ne faut pas se faire d'illusions à cet égard. L'homme est bien plus près des singes anthropomorphes par les caractères anatomiques de son cerveau que ceux-ci ne le sont non"seulement des autres mammifères, mais même de certains "quadrumanes, des guenons et des macaques." But it would be superfluous here to give further details on the correspondence between man and the higher manmals in the structure of the brain and all other parts of the body. 86 66 It may, however, be worth while to specify a few points, not directly or obviously connected with structure, by which this correspondence or relationship is well shewn. Man is liable to receive from the lower animals, and to com 'Grosshirnwindungen des Menchen,' 1868, s. 96. The conclusions of this author, as well as those of Gratiolet and Aeby, concerning the brain, will be discussed by Prof. Huxley in the Appendix alluded to in the Preface to this edition. 2Leç. sur la Phys.' 1866, p. 890, as quoted by M. Dally, 'L'Ordre des Primates et le Transformisme,' 1868, p. 29. 4 3 municate to them, certain diseases, as hydrophobia, variola, the glanders, syphilis, cholera, herpes, &c.; 3 and this fact proves the close similarity of their tissues and blood, both in minute structure and composition, far more plainly than does their comparison under the best microscope, or by the aid of the best chemical analysis. Monkeys are liable to many of the same noncontagious diseases as we are; thus Rengger,5 who carefully observed for a long time the Cebus Azaro in its native land, found it liable to catarrh, with the usual symptoms, and which, when often recurrent, led to consumption. These monkeys suffered also from apoplexy, inflammation of the bowels, and cataract in the eye. The younger ones when shedding their milk-teeth often died from fever. Medicines produced the same effect on them as on us. Many kinds of monkeys have a strong taste for tea, coffee, and spirituous liquors: they will also, as I have myself seen, smoke tobacco with pleasure." Brehm asserts that the natives of north-eastern Africa catch the wild baboons by exposing vessels with strong beer, by which they are made drunk. He has seen some of these animals, which he kept in confinement, in this state; and he gives a laughable account of their behaviour and strange grimaces. On the following morning they were very cross and dismal; they held their aching heads with both hands, and wore a most pitiable expression : when beer or wine was offered them, they turned away with disgust, but relished the juice of lemons.' An American monkey, an Ateles, after getting drunk on brandy, would never touch it again, and thus was wiser than many men. These trifling facts prove how similar the nerves of taste must be in monkeys and man, and how similarly their whole nervous system is affected. Man is infested with internal parasites, sometimes causing 3 Dr. W. Lauder Lindsay has treated this subject at some length in the Journal of Mental Science,' July 1871; and in the Edinburgh Veterinary Review,' July 1858. A Rev.ewer has criticised (British Quarterly Review,' Oct. 1st, 1871, p. 472) what I have here said with much severity and contempt; but as I do not use the term identity, I cannot see that I am greatly in error. There appears to me a strong analogy between the same infection or contagion producing the same result, or one closely similar, in two distinct animals, and the testing of two dis tinct fluids by the same chemical reagent. 5 Naturgeschichte der Säugethiere von Paraguay,' 1830, s. 50. 6 The same tastes are common to some animals much lower in the scale. Mr. A. Nicols informs me that he kept in Queensland, in Aus tralia, three individuals of the Phaseolarctus cinereus; and that, without having been taught in any way, they acquired a strong taste for rum, and for smoking tobacco. 7 Brehm, 'Thierleben,' B. i. 1864, s. 75, 86. On the Ateles, s. 105. For other anal geus statements, see s. 25, 107. fatal effects; and is plagued by external parasites, all of which belong to the same genera or families as those infesting other mammals, and in the case of scabies to the same species. Man is subject, like other mammals, birds, and even insects, to that mysterious law, which causes certain normal processes, such as gestation, as well as the maturation and duration of various diseases, to follow lunar periods. His wounds are repaired by the same process of healing; and the stumps left after the amputation of his limbs, especially during an early embryonic period, occasionally possess some power of regeneration, as in the lowest animals." 10 The whole process of that most important function, the reproduction of the species, is strikingly the same in all mammais, from the first act of courtship by the male," to the birth and nurturing of the young. Monkeys are born in almost as helpless a condition as our own infants; and in certain genera the young differ fully as much in appearance from the adults, as do our children from their full-grown parents.12 It has been urged by some writers, as an important distinction, that with man the young arrive at maturity at a much later age than with any other animal: but if we look to the races of mankind which inhabit tropical countries the difference is not great, for the orang is believed not to be adult till the age of from ten to fifteen years.18 Man differs from woman in size, bodily strength, hairiness, &c., as well as in mind, in the same manner as do the Dr. W. Lauder Lindsay, 'Edinburgh Vet. Review,' July 1858, p. 13. 9 With respect to insects see Dr. Laycock, "On a General Law of Vital Periodicity," British Association,' 1842. Dr. Macculloch, Silliman's North American Journal of Science,' vol. xvii. p. 305, has seen a dog suffering from tertian ague. Herefter I shall return to this subject. 10 I have given the evidence on his head in my Variation of Aniaals and Plants under Domesticaion,' vol. ii. p. 15, and more could De added. "Mares e diversis generibus "Quadrumanorum sine dubio di"gnoscunt feminas humanas a ma"ribus. Primum, credo, odoratu, postea aspectu. Mr. Youatt, qui "diu in Hortis Zoologicis (Besti ariis) medicus animalium erat, vir in rebu observandis cautus et two sexes of many mammals. So that the correspondence in general structure, in the minute structure of the tissues, in chemical composition and in constitution, between man and the higher animals, especially the anthropomorphous apes, is extremely close. Embryonic Development.-Man is developed from an ovulo, about the 125th of an inch in diameter, which differs ir no respect from the ovules of other animals. The embryo itself at a very early period can hardly be distinguished from that of other members of the vertebrate kingdom. At this period the arteries run in arch-like branches, as if to carry the blood to branchia which are not present in the higher vertebrata, though the slits on the sides of the neck still remain (ƒ, g, fig. 1), marking their former position. At a somewhat later period, when the extremities are developed, "the feet of lizards and "mammals," as the illustrious Von Baer remarks, "the wings "and feet of birds, no less than the hands and feet of man, all "arise from the same fundamental form." It is, says Prof. Huxley, quite in the later stages of development that the young human being presents marked differences from the young ape, while the latter departs as much from the dog in its developments, as the man does. Startling as this last assertion may appear to be, it is demonstrably true." 66 66 14 66 As some of my readers may never have seen a drawing of an embryo, I have given one of man and another of a dog, at about the same early stage of development, carefully copied from two works of undoubted accuracy.15 After the foregoing statements made by such high authorities, it would be superfluous on my part to give a number of borrowed details, shewing that the embryo of man closely resembles that of other mammals. It may, however, be added, that the human embryo likewise resembles certain low forms when adult in various points of structure. For instance, the heart at first exists as a simple pulsating vessel; the excreta are voided through a cloacal passage; and the os coccyx projects 14 Man's Place in Nature,' 1863, magnified, the embryo being twentyfive days old. The internal viscera have been omitted, and the uterine ap pendages in both drawings removed I was directed to these figures by Prof. Huxley, from whose work, 'Man's Place in Nature,' the idea of giving them was taken. Häckel has also given analogous drawings in his Schöpfungsgeschichte.' |