parts of a single scheme.260 Their connexion with each other is established, not only by a comparison of different species, but also by a comparison of different members of the same species. In human beings, for example, the locomotive and other animal functions are more active in persons of a sanguine temperament, than in those of a lymphatic temperament; while, in sanguine temperaments, the globules are more numerous than in lymphatic ones. The knowledge of this fact we owe to Lecanu ;261 and to him we are also indebted for an analogous fact, corroborating the same view. He has shown, that the blood of women contains more water and fewer red globules than the blood of men ;262 so that here again we discern the relation between these globules and the energy of animal life. Inasmuch, however, as these researches were not made until many years after the death of Hunter, the coincidence between them and his speculative conclusions is a striking instance of his power of generalization, and of that unrivalled knowledge of comparative anatomy, which supplied him with materials from which, in spite of the backwardness of animal chemistry, he was able to draw an inference,

260 The evidence of this is collected in the notes to Buckle's History of Civilization, vol. i. pp. 53-55.

261"According to Lecanu, temperament has an influence upon the composition of the blood. He infers from his analyses that the blood of lymphatic persons is poorer in solid constituents, and especially in blood corpuscules, than that of persons of sanguineous temperament, while the quantity of albumen is much the same in both." Simon's Animal Chemistry with reference to the Physiology and Pathology of Man, London, 1845, vol. i. p. 236. Compare Thomson's Chemistry of Animal Bodies, Edinburgh, 1843, p. 370.

202 Simon's Animal Chemistry, vol. i. pp. 234, 235. Subsequent experiments have confirmed this. "The proportion of red globules dried to 1000 parts of blood, is in healthy males estimated at 127 parts by Andral and Gavarret; lower and higher figures have been given by other analysts, but this probably is the result of somewhat different modes of proceeding. In females the proportion of globules is lower. Becquerel and Rodier make the difference to be about 15 parts per 1000." Jones and Sieveking's Pathological Anatomy, London, 1854, p. 23. Hence, the greater specific gravity of male blood. See the interesting results of Dr. Davy's experiments in Davy's Physiological and Anatomical Researches, London, 1839, vol. ii.

p. 32.

which later and minuter researches have decisively verified.263

Having thus, by a comprehensive survey of the animal world, associated its remarkable faculty of movement with the state of its blood, Hunter turned his attention to another aspect of the question, and took into consideration the movements of the vegetable world, in the hope that, by comparing these two divisions of nature, he might detect some law, which, being common to both, should unite into one study all the principles of organic motion. Though he failed in this great undertaking, some of his generalizations are very suggestive, and well illustrate the power and grasp of his mind. Looking at the organic kingdom as a whole, he supposed that its capacity of action, both in animals and in vegetables, was of three kinds. The first kind, was the action of the individual upon the materials it already possessed; and this gave rise to growth, secretion, and other functions, in which the juice of the plant was equivalent to the blood of the animal.264 The second

263 Hunter died in 1793. The researches of Lecanu were published in

1831.

Another, and still more remarkable proof of the extent to which Hunter outstripped his own age, appears in the following passage, which has just been published in his posthumous works, and in which he anticipates the grandest and most suggestive of all the ideas belonging to the physiology of the nineteenth century. "If we were capable of following the progress of increase of the number of the parts of the most perfect animal, as they first formed in succession, from the very first to its state of full perfection, we should probably be able to compare it with some one of the incomplete animals themselves, of every order of animals in the Creation, being at no stage different from some of the inferior orders. Or, in other words, if we were to take a series of animals, from the more imperfect to the perfect, we should probably find an imperfect animal, corresponding with some stage the most perfect." Essays and Observations by John Hunter, being his mous Papers, London, 1861, vol. i. p. 203.

The natural salutary actions, arising from stimuli, take place both Is and vegetables, and may be divided into three kinds. The first tion, or self-motion, is employed simply in the economical operawhich means the immediate functions are carried on, and the operations performed, with the materials the animal or vegetable session of, such as growth, support, secretion, &c. The blood is of by the actions of the vessels, according to their specific stimulus, ng all the above effects. The juices of a plant are disposed of ing to the different actions of the sap-vessels, arising also from their

kind of action had for its object to increase these materials; it was always excited by want, and its result was, to nourish and preserve the individual.265 The third kind was entirely due to external causes, including the whole material world, all the phenomena of which were a stimulus to some kind of action.266 By combining, in different ways, these different sources of motion, and by studying every incitement to action, first, in reference to one of the three great divisions just indicated, and, secondly, in reference to the power of action, as distinguished from the quantity of action,267 Hunter believed that some fundamental truths might be obtained, if not by himself, at all events by his successors. For, he thought that, though animals can do many things which plants cannot, still, the immediate cause of action is in both cases the same. 268 In animals, there is more variety

specific stimulus, which is different from that of blood-vessels, but equally produces growth; but a vine will grow twenty feet in one summer, while a whale, probably, does not grow so much in as many years." Croonian Lectures on Muscular Motion, in Hunter's Works, vol. iv. p. 199.

285 "The second kind of action is in pursuit of external influence, and arises from a compound of internal and external stimulus; it is excited by the state of the animal or vegetable, which gives the stimulus of want, and being completed by external stimulus, produces the proper supplies of nourishment. It produces motions of whole parts: thus we see the Hedysarum gyrans moving its lesser foliola. This is an action apparently similar to breathing in animals, though, perhaps, it does not answer the same purpose; yet there is an alternate motion in both." Croonian Lectures, in Hunter's Works, vol. iv. p. 200.

266"The third kind of motion is from external stimulus, and consists principally of the motion of whole parts, which is not inconsiderable in vegetables, as in the Dionaea muscipula and Mimosa pudica is very evident." "These actions are similar to what arise in many animals from external stimulus." Ibid., vol. iv. p. 201.

267 "I make a material difference between the power and the quantity of action. Some motions may be very small, yet act with great force; while others are of considerable extent, although very weak." Ibid., vol. iv. P. 204.

268"The immediate cause of motion in all vegetables is most probably the same, and it is probably the same in all animals; but how far they are the same in both classes, has not yet been determined. But I think it will appear, in the investigation of this subject, that vegetables and animals have actions evidently common to both, and that the causes of these actions are apparently the same in both; and most probably there is not an action in the vegetable, which does not correspond or belong to the animal, 20

VOL. II.

of motion, but in plants there is more real power. A horse is certainly far stronger than a man. Yet a small vine can not only support, but can raise, a column of fluid five times higher than a horse can. Indeed, the power which a plant exercises of holding a leaf erect during an entire day, without pause and without fatigue, is an effort of astonishing vigour, and is one of many proofs, that a principle of compensation is at work, so that the same energy which, in the animal world, is weakened by being directed to many objects, is, in the vegetable world, strengthened by being concentrated on a few 269

In pursuing these speculations, which, amid much that is uncertain, contain, I firmly believe, a large amount of important, though neglected, truth, Hunter was led to consider how motion is produced by various forces, such as magnetism, electricity, gravitation, and chemical attraction.270 This carried him into inorganic science, where, as he clearly saw, the foundation of all organic science must be laid. Just as, on the one hand, the human frame could never be successfully studied, except by the aid of principles which had been collected from

although the mode of action in the parts may not be the same, or muscular, in both." Croonian Lectures, in Hunter's Works, vol. iv. p. 196. Compare the section "Of Motion in Vegetables," in Hunter's Essays, London, 1861, vol. i. p. 24.

....

269The variety of motions is greater in animals, and more purposes are answered by them." "The first kind of action appears to be stronger in its power, although less in quantity, in vegetables than in animals; for a small vine was capable of sustaining, and even of raising, a column of sap 43 feet high, while a horse's heart was only capable of supporting a column of blood 8 feet 9 inches high; both of which columns must have been supported by the action of the internal parts, for we must suppose the heart equal, or nearly so, to the strength or action of the other parts of the vascular system; and when we consider that the sap of the tallest tree must be supported, and even raised from the root to the most distant branches, it must appear that the power of such vegetables far exceeds the power of any animal, and, indeed, it is such as the texture of a vegetable only can support. The power of supporting a leaf erect for a whole day is as great an effort of action as that of the elevator palpebrarum muscle of the eye of an animal." Hunter's Works, vol. iv. pp. 203, 204. See also Hunter's Essays, vol. i. p. 342: "It is probable that the vegetable which can the least bear a suspension of its actions, can do so more than the animal which can bear it longest."

270 Hunter's Works, vol. iv. p. 255.

271

an investigation of animals below man, so, on the other hand, the laws of those very animals must, he said, be approached through the laws of common or inorganic matter.272 He, therefore, aimed at nothing less than to unite all the branches of physical science, taking them in the order of their relative complexity, and proceeding from the simplest to the most intricate. With this view, he examined the structure of the mineral kingdom, and, by an extensive comparison of crystals, he sought to generalize the principles of form, in the same way as, by a comparison of animals, he sought to generalize the principles of function. And, in doing this, he took into account, not only regular crystals, but also irregular ones.273 For, he knew that, in nature, nothing is really irregular or disorderly; though our

271 In his Principles of Surgery, he says (Hunter's Works, vol. i. p. 220), "The human body is what I mean chiefly to treat of; but I shall often find it necessary to illustrate some of the propositions which I shall lay down from animals of an inferior order, in whom the principles may be more distinct and less blended with others, or where the parts are differently constructed, in order to show, from many varieties of structure, and from many different considerations, what are the uses of the same parts in man; or, at least, to show that they are not for the uses which have been commonly assigned to them; and, as man is the most complicated part of the whole animal creation, it will be proper, in the first place, to point out general principles, common to all this species of matter, that I may be better understood, when I come to the more complicated machine, namely,

the human."

272"Before we endeavour to give an idea of an animal, it is necessary to understand the properties of that matter of which an animal is composed; but the better to understand animal matter, it is necessary to understand the properties of common matter; else we shall be often applying our ideas of common matter, which are familiar to us, to animal matter, an error hitherto too common, but which we should carefully avoid." Principles of Surgery, in Hunter's Works, vol. i. p. 211. "In the natural history of vegetables and animals, therefore, it will be necessary to go back to the first or common matter of this globe, and give its general properties; then see how far these properties are introduced into the vegetable and animal operations; or rather, perhaps, how far they are of use or subservient to their actions." Hunter's Essays, vol. i. p. 4. Every property in man is similar to some property, either in another animal, or probably in a vegetable, or even in inanimate matter. Thereby (man) becomes classible with those in some of his parts." Ibid., p. 10.

273 He made 66 a valuable collection of crystallizations, both of regular and irregular forms, which he was accustomed to use in his lectures to exemplify the difference between the laws which regulate the growth of organic and the increase of inorganic bodies.” Ottley's Life of Ilunter, p. 138.