1 Wordsworth.
2 Crystals not only grow by assimilation, but even repair injuries, with a certain superficial resemblance to the repair of animal tissues. Thus, according to the experiments of Jordan cited by Sir James Paget (Lectures on Surgical Pathology, I. 153, and 2d ed. p. 115), an octohedral crystal of alum, if fractured and replaced in a motherlye will in a few days exhibit a complete restoration of the original form. The whole crystal increases, but the increase is greatest on the broken edge, and the octohedral form is completely renewed. (Comp. § 113.)
3 Cited by Drysdale, Life and the Equivalence of Force, Part II. p. 149.
4 Ranke, Die Lebensbedingungen der Nerven, 1868, p. 80.
5 “Il n’y a peut être pas un seul phénomène chimique dans l’organisme qui se fasse par les procédés de la chimie de laboratoire; en particulier il n’y a peut être pas une oxydation qui s’accomplisse par fixation directe d’oxygène.”—Claude Bernard.
6 Dr. Madden, in his essay On the Relation of Therapeutics to Medicine, 1871, p. 5, gives a remarkable illustration of what may be called the frustration of chemical affinity effected by mechanical conditions. “Before calico can be printed, every loose particle of cotton must be removed from the surface in order that the colored inks may not run. This removal is effected by passing the calico over and in contact with a red-hot iron cylinder, and by regulating the rapidity with which the cylinder revolves, the intense heat burns off the loose fibres, yet does no injury to the woven cloth. In other words, the changes in the relation of the high temperature and the cotton are too rapid to admit of the fibre combining with the oxygen. Let the rate of revolution be reduced but very little, and the calico would burst into flames.” Any one who has snuffed a candle with his fingers will understand this. Dr. Madden further instances certain fulminates which can be detonated in contact with gun-cotton without causing it to explode—the extreme rapidity with which the fulminates expand is too great to enable the gun-cotton to adjust its movements to this new motion. Precisely the same kind of thing occurs in organized matter. If the rate of its changes be reduced below a certain point, the ordinary chemical affinities will assert themselves.
7 I am often reminded of the surprising movements of particles of carbonate of lime in water which my friend Professor Preyer showed me during a visit to Bonn. He had removed one of the concretions, usually found in connection with nerves along the spine of old frogs, and crushed it in water; under the microscope the seeming spontaneity and variety of the movements of the particles was such that had we not known their origin we should certainly have attributed them to vitality: no infusoria could have moved with more seeming spontaneity. It is hardly physiological to conclude that because fragments of tissue manifest ambœbiform movements therefore they are alive (Stricker, art. Die Zelle in his Handbuch der Lehre von den Geweben, 1868, p. 7), or that the heart removed from the body is alive because it still beats. Lieberkühn, Ueber Bewegungserschsinungen der Zellen, 1870, pp. 357–359, cites examples of such movements in undeniably dead substances. For Life, we demand not only Movement, but Functional Activity.
8 Telesius, De Natura Rerum, 1586, V. 184. Telesio might have been saved from the mistake had he attended to what Niphus had said on the point in his Expositio subtilissima, 1559, p. 245. Comp. also Philelphus, Epist. Familiarum, 1502, p. 253, verso.
9 The authorities just cited are Aristotle, De Anima, Lib. II. c. I. Kant, Kritik der Urtheilskraft. Müller, Physiology. Beale, Bioplasm, and Introduction to Todd and Bowman’s Anatomy. Schelling, Erster Entwurf, and Transcendent. Idealismus. Bichat, Recherches sur la Vie et la Mort. Stahl, Theoria Vera Medica. Dugès, Physiologie Comparée. Béclard, Anatomie Générale. Lamarck, Philosophie Zoologique. Comte, Cours de Philosophie Positive. Owen’s Hunterian Lectures, 1854. Herbert Spencer, Principles of Biology.
10 Fletcher, as quoted by Drysdale, Life and the Equivalence of Force, Part II. p. 120.
11 Robin et Verdeil, Traité de Chimie Anatomique, 1853.
12 Paget, Lectures on Surgical Pathology, p. 14.
13 Comp. Haeckel, in Siebold und Kölliker’s Zeitschrift, 1865, p. 342, and his Generelle Morphologie, 1866, I, 135, 336.
14 In the Archiv für mikros. Anatomie, 1865, p. 211.
15 Here organization is the simplest form of all—molecular organized structure, which in the higher forms becomes tissue structure, and organ structure. The word structure properly means orderly arrangement of different materials; and molecular structure refers to the different proximate principles which constitute the organized substance. Usually, however, the word structureless indicates the absence of visible arrangement of the parts; a cell has structure since it has nucleus and protoplasm.
16 In the cell-theory established by Schleiden and Schwann, in 1838, and which has formed the basis of modern histology, the cell-wall was endowed with an importance which can no longer be upheld now that the existence of independent organisms, and of cells, without a trace of enveloping membrane has been abundantly observed. Cells without walls were first described by Coste in the Comptes Rendus, 1845, p. 1372. They were also described by Charles Robin in 1855, Dict. de la Médicine, art. Cellule. But little notice was taken until Max Schultze, in his famous essay, Ueber Muskelkörperchen und was man eine Zelle zu nennen habe, which appeared in Reichert und Du Bois Reymond’s Archiv, 1861,—Bruecke, in his memoir, Die Elementarorganismen, 1861,—and Lionel Beale, in his Structure of the Simple Tissues, 1861,—all about the same time began the reform in the cell-theory which has effected a decisive change in the classical teaching. Leydig claims, and with justice, to have furnished important data in this direction (Vom Bau des thierischen Körpers, 1864, I. p. 11). The student interested in this discussion should consult Max Schultze, Das Protoplasma der Rhizopoden und der Pflanzenzellen, 1863; Haeckel, Die Radiolarien, 1862; the controversial papers by Reichert, in his Archiv (beginning with the Report of 1863), and Max Schultze, in his Archiv für mikros. Anat., with Henle’s judgment in his Jahresberichte, and Külliker’s summing-up in the last edition of his Gewebelehre. For a full yet brief history of the cell-theory see Drysdale, The Protoplasmic Theory of Life, 1874, pp. 96–106.
17 At the time this was written, I had some fish ova in the course of development. Out of the same mass, and in the same vessel, all those which were supported by weed at a depth of half an inch from the surface, lived and developed; all those, without exception, that were at a depth of two to four inches, perished. In ordinary parlance, surely, nothing would be objected to in the phrase, “these ova were all in the same Medium”; the water was the same, the weed the same, the vessel the same; yet some difference of temperature and carbonic acid made all the difference between life and death. Another curious fact was observed; I removed eight of these ova with active embryos, and placed them in a large watch-glass containing a solution (one half per cent) of bichromate of ammonia. In this acid the embryos lived and were active fifty-seven hours, although other embryos placed in a similar watch-glass containing pond-water, survived only forty hours. The non-effect of the acid was probably due to the non-absorption which nullifies the effect of certain virulent poisons when they are swallowed; but why the fish should live longer in the acid than in the simple water, I do not at all comprehend.
18 Agassiz, Essay on Classification, 1859, p. 15.
19 Haeckel, Generelle Morphologie, II. 211.
20 See on this last point Ranke, Die Lebensbedingungen der Nerven, 1868, p. 34.
21 See Waldeyer, art. Eierstock, in Stricker’s Handbuch der Lehre von den Geweben, 1870, p. 570. “I found in a fœtus, which, in a case of extra-uterine pregnancy, had lain thirty years in the body of its mother, the structure of the muscles as intact as if it had been born at its full time.”—Virchow, Cellular Pathologie, Lect. XIV.
22 See Beale, The Structure of the Simple Tissues, 1861; the Introd. to his edition of Todd and Bowman’s Physiological Anatomy, 1866; and How to Work with the Microscope, 4th ed., 1868; also Bioplasm, 1872.
23 “The physical property of the tissue does not depend upon this matter, nor is its function due to it.”—Beale, Introduction to Todd and Bowman, p. 11. That is to say, he regards even contractility and neurility as physical, not vital facts.
24 In turning over the pages of a work which was celebrated some half-century ago—Rudolphi’s Grundriss der Physiologie—I was interested to find a clear recognition of this biological principle: “Alle Theile aller Organismen,” he says, I. 233, “sie mögen noch so verschieden in ihrem Bau, in ihrer Mischung, und in ihrer Thätigkeit seyn, sind ohne Ausnahme als organisch und mithin als lebend zu betrachten.” In a note he adds that physiologists have considered certain solid parts—epidermis, nail, hair, and bones—to be dead; “but all these are organically developed, and are in direct connection with the other parts.”
25 Virchow, Die Cellular Pathologie, 1860, Lect. I.
26 Beale, Bioplasm, 104.
27 Kölliker, Gewebelehre, 5th ed., 1867, p. 12.
28 Nevertheless there are some facts directly contradicting his conclusions. For example, he considers the axis cylinder of the nerve to be formed material, and agrees with Max Schultze and others as to its fibrillated structure; yet according to Lister and Turner, Gerlach and Frey, the axis cylinder is deeply stained by carmine, and in this respect resembles the nucleus of protoplasm.
29 From the quite recent experiments M. Baillon has submitted to the Académie des Sciences (15th February, 1875), it appears that although cut flowers absorb colored fluids, the roots when intact only absorb the fluid, and reject the coloring matters, by a veritable dialysis.
30 Gerlach cited by Ranke, op. cit., p. 76.
31 Stein, Der Organismus der Infusionsthierchen, 1859, p. 76.
32 Stahl had a profound conviction of the radical difference, though he was not able to point out the conditions involved. See his Disquisitio de mechanismi et organismi vera diversitate.
33 M. Fernand Papillon has shown that animals may be fed with food deprived of phosphates of lime if its place is supplied with magnesia, strontia, or alumina; they make their bones out of these as out of lime. But no such substitution is possible in muscle, nerve, or gland; we cannot replace the phosphate of magnesia in muscles by the phosphate of iron, lime, or potash, as we can replace the iron of a wheel by steel, copper, or brass.
34 Anatomy resolves the Tissues into Organites (cells, fibres, tubes); here its province ends, and that of Chemistry begins by pointing out the molecular composition of the Organites.
35 This luminous conception, though vaguely seized by Pinel, was first definitely wrought out by Bichat. See his Recherches sur la Vie et la Mort—and especially his Anatomie Générale, 1812, I. p. lxx. It was one of the most germinal conceptions of modern times.
36 Just as there go other materials besides canvas to make a sail, and others besides iron to make a windlass, so there go other tissues besides the muscular to form a muscle—there is the membranous envelope, the nerve, the blood-vessels, the lymphatics, the tendon, and the fat. Even in Contraction there is another property involved besides the Contractility of the muscular element, namely, the Elasticity of the fibrous wall of the muscular tube; but Contractility is the dominant property, and determines the speciality of the function.
37 “L’élément musculaire peut être annexé à une foule de mécanismes divers; tantôt à un os, tantôt à un intestin, tantôt à une vessie, tantôt à un vaisseau, tantôt à un conduit excréteur, tantôt enfin à des appareils tout à fait spéciaux à certaines espèces d’animaux.”—Claude Bernard, Rapport sur les Progrès de la Physiologie générale, 1867, p. 38.
38 Vulpian, Leçons sur la Physiologie du Système Nerveux, 1866, p. 581. In a work just published I find M. Luys hesitating at the consistent application of this law. After pointing out the identity of the tissue in cerebrum and spinal cord, he is only prepared to say that we cannot deny that there is no impossibility in admitting physiological equivalence where there is morphological equivalence.—Luys, Actions Reflexes du Cerveau, 1874, p. 14.
39 It is because men converted the result into a principle, and supposed that Life preceded the Organism, that they were led to puzzle themselves over such facts as the continuance of vitality in divided organisms. Aristotle felt the force of the objection: “Plants when divided are seen to live, and so are certain insects, as if still possessing the same Vital Principle (ψυχή) considered specifically (τῷ εἴδει) though not the same numerically (μὴ ἀριθμῷ). Each of these parts has sensation and locomotion for a time; and there is no room for surprise at their not continuing to manifest these properties, seeing that the organs necessary for their preservation are absent.”—De Anima, Lib. I. Ch. IV. Compare Basso, Philos. Naturalis adversus Aristotelem, Amsterdam, 1649, p. 260; and Taurellus, Contra Cæsalpinum, 1650, p. 850; neither of them grappling with the difficulty so firmly as Aristotle.
40 Spencer, Principles of Biology, 1864, I. 153.
41 Comp. Lamarck, Philos. Zool., II. 114.
42 Comp. Spencer, op. cit., II. 362, 363, for good illustrations of this.
43 Agassiz, Essay on Classification, p. 91.
44 “Nulla in corpore animali para ante aliam facta est, et omnes simul creatæ exiatunt.”—Haller, Elementa Physiologiæ, VIII. 148.
45 Quatrefages, Metamorphoses de l’Homme et des Animaux, 1862, p. 42.
46 Von Baer, Ueber Entwickelungageschichte, 1828, I. 221.
47 Curiously enough, while the Nudibranch, which is without a shell, possesses one during its embryonic life, there is another mollusc, Neritina fluviatilis, which possessing a shell in its subsequent life is without one during the early periods, and according to Claparède begins an independent existence, capable of feeding itself before it acquires one. See his admirable memoir on the Neritina, in Müller’s Archiv, 1857.
48 Has any advocate of the hypothesis that animals were created as we see them now, fully formed and wondrously adapted in all their parts to the conditions in which they live, ever considered the hind legs of the seal, which he may have watched in the Zoölogial Gardens? Here is an animal which habitually swims like a fish, and cannot use his hind limbs except as a rudder to propel him through the water; but instead of having a fish-like tail he has two legs flattened together, and nails on the toes—toes and nails being obvious superfluities. Now which is the more rational interpretation, that these limbs, in spite of their non-adaptation, were retained in rigid adherence to a Plan, or that the limbs were inherited from an ancestor who used them as legs, and that these legs have gradually become modified by the fish-like habits of the seal?
49 Milne Edwards, Intro. à la Zoologie Générale, 1851, p. 9.
50 Von Baer, op. cit., I. 203.
51 Wolff, Theorie der Generation, 1764, § 67. The reader will find abundant and valuable corroboration of this biological principle in Sir James Paget’s Lectures on Surgical Pathology.
52 Von Baer, Selbstbiographie, 1866, p. 319.
53 Milne Edwards, Intro. à la Zoologie Générale, 176.
54 Von Baer, Ueber Entwickelungsgeschichte, I. 147.
55 Lotze, art. Lebenskraft, in Wagner’s Handwörterbuch der Physiologie, p. XXVI.
56 I had kept these tritons four years in the hope that they would breed; but in spite of their being subjected to great varieties of treatment—for months well supplied with food, and for months reduced almost to starvation—they never showed the slightest tendency to breed; another among the many illustrations of the readiness with which the generative system is affected even in very hardy and not very impressionable animals. Claparède observed the still more surprising fact that the Neritina fluviatilis (a river snail) not only will not lay eggs, but will not even feed in captivity. He attributes it to the stillness of the water in the aquarium, so unlike that of the running streams in which the mollusc lives. See Müller’s Archiv, 1857.
58 Darwin, On Domestication, II. 340. In the Annales des Sciences, 1862, p. 358, M. Malm describes a fish in his collection, the tail of which had been broken, and the bone which grew out at the injured spot had formed a second tail with terminal fin.
59 In the memoir on the Anatomy and Physiology of the Nematoids, by Dr. Charlton Bastian, which appeared in the Philosophical Transactions for 1866, we read that even these lowly organized worms have little power of repair. Speaking of the “paste eels” (Anguilulidæ), he says, “I may state as the result of many experiments with these that the power they possess of repairing injuries seems very low. I have cut off portions of the posterior extremity, and though I watched the animal for days after, could never recognize any attempt at repair.” Perhaps, however, the season may have some influence; and Dr. Williams’s denial respecting the Naïs may be thus explained. [What is said above was written in 1868, and published in the June number of the Fortnightly Review. In the August of that year the question of reproduction of lost limbs was treated by Prof. Rolleston in his Address to the British Medical Association, in which he showed cogent evidence for the conclusion that the reproduction of limbs only exists is animals that have feeble respiration, and consequently slow vital processes.]
60 This beautiful and transparent larva reminds one in many respects of the Pike as it poises itself in the water awaiting its prey. It is enabled to do so without the slightest exertion by the air-bladders which it possesses in the two kidney-shaped rudiments of tracheæ, and which in the gnat become developed into the respiratory apparatus. The resemblance to the air-bladder of fishes is not simply that it serves a similar purpose of sustaining the body in the water, it is in both cases a rudiment of the respiratory apparatus, which in the fish never becomes developed. Weismann calls attention to an organ in the larvæ of certain insects (the Culicidæ), which have what he calls a tracheal gill, which gill has this striking analogy with the fish-gill that it separates the air from the water, and not, as a trachea, direct from the atmosphere. See his remarkable memoir Die nachembryonale Entwickelung des Muscidens, in Siebold und Kölliker’s Zeitschrift, 1864, p. 223.
61 The Variation of Animals and Plants, 1868, II. p. 272.
62 Origin of Species, 5th ed. p. 96.
63 Mr. Darwin has himself, in the following passage, stated a somewhat similar view, and rejected it: “In one sense the conditions of life may be said not only to cause variability, but likewise to include Natural Selection, for the conditions determine whether this or that variety shall survive. But when man is the selecting agent, we clearly see that the two elements of change are distinct; the conditions cause the variability, the will of man acting either consciously or unconsciously accumulates the variations in certain directions, and this answers to the survival of the fittest under nature.” (p. 168.)
64 Even in the nerve-sheaths of some Annelids there are muscles.
65 Spencer, Principles of Biology, II. 72
66 Faivre, Variabilité de l’Espèce, p. 15.
67 These luminous organs would furnish an interesting digression if space permitted it. The student is referred to the chapter in Milne Edwards’s Leçons sur la Physiologie et l’Anatomie Comparée, 1863, VIII. 94, sq. Leydig, Histologie, 1857, p. 343. Kölliker, Microscopical Journal, 1858, VIII. 166, and Max Schultze, Archiv für mikros. Anat., 1865, p. 124. My friend Schultze was kind enough to show me some of his preparations of the organs of Lempyris splendidula, from which the drawings in his memoir were made. They reminded me of the electric organs in fishes by a certain faint analogy, the trachea in the one holding the position of nerves in the other. I may remark, in passing, that it is not every phosphorescent animal that has distinct luminous organs. There is a lizard (Pterodactylus Gecko) which occasionally becomes luminous. “A singular circumstance occurred to the colonial surgeon, who related it to me. He was lying awake in bed when a lizard fell from the ceiling upon the top of his mosquito-curtain; at the moment of touching it the lizard became brilliantly luminous, illuminating the objects in the neighborhood, much to the astonishment of the doctor.” Collingwood, Rambles of a Naturalist, 1868, p. 169.
68 Max Schultze, Zur Kenntniss der electrischen Organe der Fische, 1858–9.
69 Leydig, Histologie, 1857, p. 45.
70 Owen, Anatomy of The Vertebrates, 1866, I. 358.
71 Davy, Researches, Physiological and Anatomical, 139, I. 33.
72 “If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous successive slight modifications, my theory would absolutely break down.”—Darwin, Origin of Species, 5th ed. p. 227. In several passages insistence is made on this. “Natura non facit saltum” may be perfectly true; but without impugning the Law of Continuity we may urge that the Law of Discontinuity is equally true. The one is an abstract ideal conception; the other is a concrete ideal conception. According to the one, every change from rest to motion, or from one state to another, must pass through infinites; according to the other every change is abrupt. In my First Series, Vol. I. p. 327, I have shown how, on mechanical principles, every change in an organism must be abrupt. A glance at the metamorphoses of the embryo, or the stages of insect-development, will show very sudden and abrupt changes. Let me also cite Mr. Darwin against himself: “When we remember such cases as the formation of the more complex galls, and certain monstrosities, which cannot be accounted for by reversion, cohesion, etc., and sudden, strongly marked deviations of structure, such as the appearance of a moss-rose on a common rose, we must admit that the organization of the individual is capable through its own laws of growth, under certain conditions, of undergoing great modifications, independent of the gradual accumulation of slight inherited modifications.”—Origin, p. 151. See also note to § 130, further on, p. 142.
73 On the Nutrition of Monads, see the remarkable memoir by Cienkowski, in the Archiv für mikros. Anatomie, I. 221, sq.
74 Paget, Lectures on Surgical Pathology, edited by Turner, 1865, p. 19.
75 It has recently been shown that certain Crustacea vary not only from species to species, but from genus to genus, when living in water of different degrees of saltness. By continued dilution of the salt water an Artemia was developed into another species, and this again into a Branchipus—a genus of large dimensions, with an extra abdominal segment, and a different tail; a genus, moreover, which is propagated sexually, whereas the Artemia is parthenogenetic, as a rule. See Nature, 1876, June 8, p. 133.
The exceeding importance of this fact is, that it proves specific and even generic differences to originate simply through the gradual changes of the medium and the adaptation of the organism to these new conditions. It also disproves the very common notion—adopted even by Mr. Darwin himself—that “organic beings must be exposed during several generations to new conditions to cause any appreciable amount of variation.” Again, “Natural Selection, if it be a true principle, will banish the belief of any great and sudden modification of structure.”—Comp. note to § 121, p. 132.
76 Compare Leydig, Vom Bau des thierischeu Körpers, 1864, p. 27.
77 Ferdinand Cohn, Die contractile Gewebe im Pflanzenreich, 1862. By a series of numerous well-devised experiments, Cohn found that in the stamen of the centauria a tissue exists which is excitable by the same stimula as muscle is, and which reacts like muscle, describing a similar curve when excited, and, after reaching its maximum, relaxing. Like the muscle it becomes fatigued by repeated contraction, and recovers its powers by repose. Like the muscle it may be rendered tetanic. (The researches of Dr. Burdon Sanderson and Mr. Darwin have since placed beyond a doubt the Contractility and Sensibility of certain plants.)
78 Mivart, The Genesis of Species, 1871, p. 23.
79 Dohrn, Der Ursprung der Wirbelthiere und das Princip des Functionswechsels, 1875, p 74.
80 Sigmund Mayer, Die peripherische Nervenzelle und die sympathische Nervensystem, 1876.
82 These terms designate the surface aspect of a transverse section, of what more correctly should be called the gray columna. See Figs. 3 to 6.
83 But this only in the higher animals. In reptiles and amphibia the medulla descends into the cervical region, as far as the second and third cervical vertebræ. This should be remembered in experimenting.
84 Foster and Balfour, Elements of Embryology, Part I., 1874. Comp. Schwalbe, art. Die Retina, in the Handbuch der Augenheilkunde of Graefe and Sämisch, 1874, I. 363.
85 The development of the olfactory lobe and bulb is similar; it need not be followed here.