GROWTH, AND LONGEVITY. 107 return of April to us, with its buds and blossoms, makes such a subject of speculation seasonable; and as trees, whether in the garden, the field, or the forest, are universal favourites, we do not doubt that our readers will be obliged to us for bringing before them some of the views held respecting them by one who has loved them much, and studied them long with the observant eye of a genial naturalist, and the profound reflection of a true philosopher. The common and almost universally held notion of a tree is stated by Dr. Harvey, thus “The common notion of a tree is that it is an individual, in the same sense that a dog or a horse is; and it certainly appears to be such. It is assumed that the trunk and roots, and branches, the leaves and flowers, and fruit and buds, which form component parts of every tree, go to make up one and the self-same plant, in like manner as the bones and flesh, the nerves and bloodvessels, the heart and lungs, the head and trunk and limbs of a dog, do truly form the parts of one and the self-same individual animal. Doubtless, that is the common belief. A tree is regarded as having the same sort of individuality or personality that you or I have." Dr. Harvey's own notion of a tree is very different from this : “In my view it is not an individual in the proper or scientific, sense of the term, but, on the contrary, a body corporate. Take an oak at Midsummer, in full leaf, and in its full vigour. It is neither more nor less than a collection, an aggregate, a corporation of living and growing but separate and distinct oak plants, the production of the current year, and likewise of the dead remains of a still larger number of individual plants of the same kind or species, the production of a series of by-gone years. And of these oak plants, each and every one lives only one year, and attains its full growth within the year; making provision in the form of buds for the evolution of similar plants the following year. Further, the plants of each year, shooting up in spring from the buds formed by the plants of the previous year, grow parasitically on the persistent dead remains of these. Acquiring their maturity in summer, and reaching to the height of a few inches only, they pass into the state of old age (the sere and yellow leaf) and eventually die in autumn, save only the buds they have formed, which survive the winter. And thus dying, the greater part of every one of them speedily undergoes decomposition and disappears. The woody stems and roots alone remain. These, although dead, escape that process. Tipped with the living buds they abide entire-as entire, yet as destitute of vitality, as the table I am writing at; and they abide to serve to these buds and to the young oak plants that are to come of them next year (as the earth does to the acorns and their produce), the purposes both of a temporary soil and of a permanent mechanical support. Such is my apprehension of a tree. A tree is an aggregate of annual and comparatively small-sized and slender plants, the propagation of which, from year to year, is effectually provided for by buds; and the accumulation of which en masse, by the living growing as parasites on the dead, necessarily keeps pace with the annual succession of plants.” All this seems strange and paradoxical enough, but the consequences of such a theory of trees appear much more strange and paradoxical still. “Regarding the tree in this light," continues our author, “I hold that but for accidental causes, any and every tree might live for ever, and go on growing and enlarging to any conceivable size. You have heard it said that the king of England never dies ; and you will readily understand that what is not true of individual men may yet be true of individual families, or of the race in general. Individuals die, but the race lives and multiplies.* The corporation of London has lasted, we may say has lived, some hundreds of years; and unless swept away by some such extraneous cause as an act of the legislature, may last till the end of time, though the individuals composing it may none of them pass the allotted three-score years and ten. Just so in respect of a tree. If what I have stated be a true account of its nature, and of the manner of its production, it will of course follow that a tree is an individual in precisely the same sense as a body corporate ; and that, contrary indeed to the common opinion, but in perfect consistency with the principle that all living beings are subject to the law of mortality, and have a definite size or bulk of organism, there will be no limit except from extraneous causes, to the size it may attain, or the number of years it may live. What is called a genealogical tree is constructed very exactly on the principle of this theory, and serves extremely well so far to make it intelligible; while the personality of each member of the tree is admitted, and his own individual temporary existence, he is yet regarded as forming a scion or branch of one common stock, which may have had its origin in a remote age, and may endure as long as the world itself." Here, then, are questions raised of great scientific interest and diffi. culty, and which can only be settled by the most profound and comprehensive study of the principles of vegetable physiology, and the observed facts of the vegetable kingdom. We cannot, of course, in this place, follow Dr. Harvey into the details of the scientific investigations and reasonings into which he enters in support of his favourite theory ; nor in questions of abstruse science, on which the greatest masters of physiology are still divided, will we be so bold as to pronounce an opinion either way. But we may, at least, express our sense of the truly philosophic spirit and tone in which he conducts his argument, in which we recognise the genuine temper of the Baconian school ; and we cannot with hold our admiration of the enthusiastic ardour with which he has collected relevant facts and observations from all quarters, and of the acuteness and ability with which he applies them to the support of his views, and to the solution of difficulties and objections raised against those views by other physiologists. The inferences which Dr. Harvey himself deduces from his theory, viz., that there is no natural limit prescribed by the inherent physiology of the tree, either to its size or longevity, will probably appear to most people to be a sufficient prima facie argument against its truth; and as this branch of the subject admits of easy and popular treatment, we may here give a few more paragraphs from the author, both for their inherent interest, and as a sample of bis matter and manner as a scientific writer. He meets the natural incredulity with which his views respecting the indefinite growth and longevity of trees are sure to be met, by adducing many actual examples of trees of enormous size and age, which are irreconcileable with the opposite theory of a fixed and invariable law of growth and longevity. "Of old trees still extant in this country, and still living and growing, we need not look beyond the yew tribe. There are, indeed, oaks, liznes, sycamores, chesnuts, ashes, and others of great antiquity and vast size, some of them coeval with the Conquest, some of them probably much older still ; but they all sink into insignificance before the yews. Of these, there are some at Fountain's Abbey, near Ripon, in Yorkshire, which are believed to be more than 1,200 years old; there are two in the churchyard of Crow. hurst, in Surrey, 1,450 ; and one at Fortingall, in Perthshire, from 2,500 to 2,600 years * Hæc Naturæ lex, hoc consilium, ut singuli pereant homines, gens humana floreat. GROWTH, AND LONGEVITY. 109 old. One in Brabourn churchvard, in Kent, is said to have attained the age of 3,000 years; and another at Hedsor, in Bucks, which is still in full vigour, and measures abore twenty-seven feet in diameter, is reckoned to be above 3,200 years old. . . . . In the Brazils, in one of the primæval forests, there are some trees supposed to be Cour. barils, which in respect of size are truly colossal, and in respect of age have been variously computed at from 2,000 to 4,000 years. 'Never before,' says Martius, 'had I beheld such enormous trunks. They looked more like living rocks than trees; for it was only on the pinnacle of their bare and naked bark that foliage could be discovered, and that at such a distance from the eye that the form of the leaves could not be made out. Ffteen Indians, with outstretched arms, could only just embrace one of them. At the bottom they were eighty-four feet in circumference and sixty feet where the boles became cylindrical, .... Then there is the famous Boabab growing in Senegal, and supposed to be the oldest kind of tree in any part of the world. The trunk of this extraordinary tree does not attain a height much exceeding fifteen feet, but in some instances it is from eighty to ninety feet in girth : and according to the estimate of Adanson, founded on a comparison of Thevet's account of one seen by the latter in the year 1555, with his own measurement of the same tree, two hundred years later, the trees that are twenty-seven feet in diameter, have an age of 4,280 years; some of them have a diameter of thirty feet, and these are supposed to have attained an age little short of 6,000 years. Coeval, probably, with the Boabab, is the Gum-Dragon tree (Dracena Draco), which furnishes the astringent resin called dragon's blood, once used in medicine, but now chiefly by painters, as a red varnish. One growing in its native island, Teneriffe, is described by Humboldt as the “gigantic tree of Orotava”-centuries ago an object of Veneration to the Guanchos, the aborigines of Teneriffe. A little above ground it measures forty-five feet in circumference, a girth, indeed, which, vast as it is, comes far short of that of the boabab. The tree, however, seems to be of exceedingly slow growth, so much so, that, according to the traditions of it which have been handed down, it was as large and hollow 450 years ago as it is now. Sir William Hooker observes, regarding it, that it is of "incalculable age.” “Doubtless it and the boabab,” he adds, “are among the oldest vegetable inhabitants of our planet. ... The Taxodium Distickuin (or deciduous cypress) seems to be the most gigantic of any on record, and to be second to none in age. Two existing specimens may be referred to one in the churchyard of Santa Maria de Telsa, near Oaxaca in Mexico, which has a trunk ninety-three feet in girth; the other, that of Chapultepec, which is said to have a circumference of 117 feet 10 inches. Regarded as of wondrous' magnitude by the Spanish conquerors, this tree of Chapultepec 'certainly reaches back' (according to De Candole) 'to the origin of the present state of the world—an epoch of which' (in his view) it is the most indisputable monument.' Professor Henslow, it may be observed, estimates the longevity of the taxodium at above 4,000 years. ..Let these examples suffice. Enough appears from them to show that trees may attain to an age altogether wonderful, and to a size that is quite prodigious, and still continue to live and grow." But the popular objection to Dr. Harvey's theory may take another shape. Why, it may be asked, upon the principles of that theory, should examples of trees of enormous size not be extremely common ? And had our space permitted, we would gladly have added to the above extracts a series of highly interesting paragraphs, in which Dr. Harvey very satisfactorily meets this objection and disposes of it. We can only find room for a few of the leading sentences :-- “All troes, and some kinds more than others, are subject to certain influences from with ut, and to a certain change from within, which, unfailingly entail not the natural decline and death, but the accidental destruction of the far greater number of them, and that before the lapse of any very lengthened period.”—“In old trees of the Erogenous kind, the internal and more recently formed layers of bark are prevented from yielding by the drying and hardening of the olderlayers of bark without; while the inner and older wood loses its porosity, partly by the pressure of the younger wood without, and partly from deposits scrystalline J of organic matter in its substance. And thus it happens that neither can the roots of the growing plants (the annual shoots and leaves) readily find room to grow, nor can the sap rise freely upwards. In Endogens the trunk becomes at length so disproportional in height to the naturally narrow basis of sustentation under ground, as to be easily blown down. And even in Erogens, proportionally broad as this basis is, the vast height and breadth of surface which they at length acquire, cause the wind to act on them to their destruction, the older they become, at an advantage infinitely greater than in their earlier years. . . . Further, all dead organic matter' (such as Dr. H. maintains all the parts of a tree, except the year's growth, to be) ‘sooner orlater undergoes certain purely chemical changes, which lead to its decayanddecomposition, and end in its disappearance; and this process once begun goes on all the more rapidly that the conditions favourable to it obtain. . . . . Moreover, the nourishment existing in the soil comes often to be exhausted, and even that supplied by the atmosphere, to be rendered unavailable. . . . Add to the agency of the causes already specified, that of a thousand other destructive influences, frost, fire, hurricanes, lightning, the necessities and caprices of man himself; and a calculation of chances will put it beyond all doubt, that the far greater number of all sorts of trees, perennial as the everlasting hills, as I maintain they maturally are, must perish at movery remote period from their origin; and that ultimately, though at no definite time, even the oldest and the greatest of them must disappear from off the face of the earth.” The view, given in these letters, of the nature of trees, differs widely from that commonly received among us. It neither represents the popular belief, nor does it accord with the recognised doctrines of the schools. “To the popular mind, indeed,” to use Dr. H.'s own words, “it may be said to be nearly unknown, while heretofore it has failed to secure the sanction of the greater number of our scientific botanists. In the main, however, it is the same as that first set forth by De la Hire, as long ago as 1708, and subsequently held by Darwin, Mirbel, Du Petit-Thouars, Gaudichaud, and other physiologists;” and since the publication of this volume, Dr. Harvey has ascertained that the views of the eminent French physiologist, De Candolle, as set forth in his “Physiologie Végétale,” published in 1832, are substantially accordant with his own. He #. therefore, “all pretensions on the score of originality. He has advanced nothing that was not known or held before. The only merit he is disposed to claim in connection with it, is that of having unfolded it more systematically, and in greater detail than any of his predecessors.” At the same time, it is no more than justice to Dr. Harvey to state that the theory was worked out by him, substantially as it now appears, without any assistance from others; that it was embodied in a course of lectures on physiology, which he delivered in Marischal College, Aberdeen, during the winter session of 1844, and that it was subsequently more largely developed in a paper “On the Nature, Longevity, and Size of Trees,” which he published in the “Edinburgh New Philosophical Journal,” for January, 1847, long before he had any knowledge of the writings of De la Hire, Darwin, Mirbel, Gaudichaud, and De Candolle. We have only room to add that Dr. Harvey studies and expounds his MINISTERIAL MENDICANCY. 111 favourite subject, not only with the broad and acute intellect of a philosopher, but with the devout and reverential spirit of a Christian. He has an open eye for the manifestation of God in the book of nature; and he has a fine gift for discovering and appreciating the beautiful analogies which bind together the volumes of nature and revelationthe Old Testament and the New of God's Universal Bible. To him, the Trees of the field and the forest are “The Trees of the Lord," and the Cedars of Lebanon are the Cedars which “He hath planted.” Such a man and sueh a writer is a distinguished ornament to the eldership of our Chureh; and this ingenious and truly original work will find its way, we doubt not, to the hands of many of our ministers, elders, and people, who, while thankful to see examples of the combination of genius and piety appearing in any and every branch of the Church of Christ, are sensible of a special obligation to appreciate and encourage them, when they shew themselves in their own. MINISTERIAL MENDICANCY. You wish my advice as to your proposed begging expedition to clear away the debt on your church. Your question has sent back my thoughts to some old experiences of my own in the same matter. I was a more sanguine and a younger man then. The mission I undertook was not on behalf of my own church, but of a distant one in which I felt an interest, and the importance of which gave it, I thought, strong claims upon the friends of the church. I was not much in love with the work I had undertaken, and yet I fancied that the obvious generosity of my errand in pleading the cause of so important and necessitous a church, with which I had no more connection than any other member of our body, would secure for me a kindly welcome, perhaps an ample response. I am bound to say I met with many large-hearted and liberal men; some who aided me freely, others who were unable to do so only because the Tery largeness of their benefactions in other directions had too much drained the resources of their charity. I confess, howerer, that even in the case of some who gave most largely, I was not without some compunction in accepting the gift, because it was evident that the spontaneous impulses of benevolence would have sent forth the same streams to water other arid places. I felt that such donors would have given as much, more cheerfully, and perhaps with a finer exercise of heart, because spontaneously, if I had not been obliged to constrain them with the claim I carried. Of course I met with men of another class, who had no great love for giving at all. I found it a matter of extreme difficulty to show them what conceivable claim the church of — could have upon them. True, I bad in every instance sent before me a circular plainly stating the facts, which spoke for themselves more eloquently than I could do, and explaining that I went on my mission with the full sanction of my Presbytery. But what avail your circulars if men will not read them ? In four cases out of five, on the most moderate calculation, the circular was unread. I had sundry painful experiences; sometimes I had to stand in a back |