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tude of human curiosity they sought in cultivation the solution of this problem. In vain did experience disprove this system. They went beyond our record and remembrance, and hid in the obscurity of antiquity the ignorance of an origin which they were forced to admit must be sought after the creation.

never determined, and they attributed to these unknown causes the variegated coloring of flow. ers and the diversified foliage of trees, together with the extraordinary forms of those fruits which offer excrescences in the pericarp, or other similar phenomena. All these opinions have reigned for centuries among agriculturists, and it is but reThis theory, nevertheless, could not be sufficently that they have begun to forsake them. It ciently satisfactory to explain the origin of some is certainly interesting to discuss them, and imnew races which they had seen appear in gar- portant to establish or refute them. This is the dens under the eyes of their contemporaries. task which I have undertaken. I have employed my leisure in examining them with the principles of a severe philosophy, and submit them to the analysis of observation and experience. The first fact which it was necessary to examine was to know if wild trees existed which the graft or culture has changed into fine varieties. This question holds the solution of a problem of vegetable physiology which appears not to have hitherto occupied the learned, viz.: What is the influence of these agents (the graft and cultiva tion) on vegetables?

The graft and the slip (cutting) then came to the assistance of cultivators. They commenced by believing that the subject or stock grafted can sometimes influence the grafted bud in modity ing its juices, and they imagined the existence of extraordinary grafts which, uniting very different species, seemed destined to produce new races having the characteristics of both.

Others attributed these marvellous fruits to some capricious combinations formed by the union of two buds. Others finally established, in substance, that by the single fact of the graft being repeated several times on the same individuals an improvement in the plant was obtained.

There have been agriculturists who thought themselves able to change or modify the taste of vegetable productions either by infusing the seed in substances sugared or aromatic, or by the introduction of these substances into the pith of the plant; and the ill-success of these operations was always attributed to a defect in the manner of proceeding rather than to an insufficiency of the means employed.

ART. III.--Influence of the graft upon vegetables.

It must certainly be acknowledged that the graft as well as the culture and soil may influence the development of vegetable organs. A grafted tree is an individual forced to live upon a stock not its own, but from which it must draw its nourishment, so that only the subject of the graft can be assimilated to the soil. If its organs are adapted to furnish the graft all the aliment of which it can make use, then the graft. will take on an extraordinary growth, which it It is to these different methods that have been would not have equalled on a less thrifty stock. attributed all the phenomena of the vegetable If the stock which bears it be unable by its orsystem, of which the cause was not understood.ganization to supply the food it needs, then will it Thus it has been believed, and is still believed remain meagre and spindling. perhaps, that the absence of spines and down belonging to certain vegetables is only the effect of the change of climate, of long cultivation, or of the graft.

In like manner, to the multiplication by slip or by layer, the loss of the pistils of certain plants, and the sterility of certain fruits have been attributed, in which fruits it was believed that this method of multiplication acts to obliter ate the female parts and to increase the volume of the fruit. The lack of proofs was hidden in the necessity of following those methods during a succession of several generations, and the system was supported by the example of several sterile plants, such as the Persian lily, the snowball, the syringa, and many other ornamental bushes; and on that of the barberry bush, the medlar tree, without seeds, &c. This theory could not, it is true, be extended to annual or biennial plants which the seed produce every year, and in which we so often see examples of sterile flowers. But they found in their principles a very plausible explanation of sterility, and they attributed the double and semi-double flowers to the force of cultivation, imagining that this agent, aided by surrounding substances, occasioned the transformation of the fructifying parts into petals.

Finally, wishing to give an explanation of those monstrosities which the vegetable world constantly presents, they regarded them as diseases produced by exterior causes which they have

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These different circumstances, as well as the culture, may produce the phenomena presented by the wild service tree (Sorbus Aucuparia), which, grafted upon the hawthorne, (Mespylus Oxyacantha) grows, it is said, with more than usual rapidity, and attains more than its wonted height and fruitfulness. Also that of the wild apple, which, grafted upon the paradise apple, becomes a slender shrub whose branches grow hardly ten feet high.

These phenomena are due only to the abun. dance or lack of nourishment, and present no other effect than a greater or less development of the different parts of the plant. We remark one thing still more striking in ordinary grafts. Every grafted plant appears to display, at least for a time, a luxuriance of foliage more marked than the seedling, for instance, if the graft has been put into an individual of this nature; but this is due to a very simple cause. The seedling develops many branches. It gives fruit generally once in two or three years, and when it does bear, the tree is so loaded down that it can only nourish them all with difficulty. From the time it is grafted several changes are effected. Its plump and bushy top disappears and is replaced by a single branch, which has for its own nourishment all the sap which supported that large quantity of foliage. To be sure the graft may enlarge afterwards, but it never replaces the quantity of branches whica crowned the original tree. A grafted tree is always less large and

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bushy, and hence the foliage is better nourished and more beautiful, and its fruits, which are less abundant, are of greater size and more agreeable flavor.

Another circumstance also influences, perhaps, the greater elaboration of fruit in the grafted

tree.

The graft unites a branch of one variety to a stock of another variety. This union, which is not natural, forms always a kind of knot at the point of insertion, which may check the rapidity of the flow of sap; and we know that on account of this slowness in the current of the sap, buds fed by it produce fruit rather than branches.

A tree which bears but little may be rendered fruitful by rubbing off the bark at its foot. The cultivators of vineyards bend the vines or break them a little at the place where they wish the fructification to commence; and I have several times obtained oranges of extraordinary size by twisting the branch which bore them.

All these means have been long known to cultivators, and it is no longer doubtful that this effect is due only to the great slowness in the flow of the sap, which thus influences the quantity and quality of the fruit.

But such are the limits which nature has fixed to the influence of the graft upon vegetables. It facilitates or improves their development, but never changes or modifies their forms, juices, or colors. Never has the wild pear been transformed by the graft into the butter pear, nor the butter pear into the muscat pear; never has the bitter orange been so improved as to lose its bitterness by grafting. I have a stock of this species which I have grafted three times upon itself, graft upon graft, but it gives me only larger fruit, differing in no other way from that of the plant which furnished the bud.

The graft is nothing more than a kind of slip. It transfers the bud of one plant to the stem or body of another; and this bud, which encloses within itself the rudiments of the vegetables destined to grow from it, draws from the stock on which it is placed the juices necessary for its nourishment in the same manner as the slip draws them directly from the earth. It is possible that, from the passage which these juices are forced to make through the roots and trunk of the plant, they reach the fibres of the bud more claborated than if drawn more directly from the soil; but whatever may be their condition when they enter the bud, they are there always modified by its organs as are those elements drawn from the air, and as those taken from the earth would be, if it were placed with its own roots directly in the soil.

Experience has confirmed these principles, and it is now established that the graft is useful only in perpetuating species or varieties without improving them. I have made constant observations on this subject during more than fifteen years, by keeping beside the grafted plant the plant which furnished the bud. I have grafted oranges upon lemons and lemons upon oranges. I have grafted sweet oranges upon bitter oranges and bitter oranges upon sweet ones; apricots on prunes and peaches upon apricots; and I never could recognize the least difference between the fruits given by the plant which furnished the graft and those of the plant which received it. I never obtained from these operations any other

result than that of preserving rare varieties, which could not be propagated by seed, for the double reason that they but rarely contained any, and that when they did, we could obtain from them usually only degenerated varieties.

The theoretic principles which prove the insufficiency of the stock and of the sap to effect changes in the product of the graft, can not be equally applied to those remarkable grafts formed by the union of two or three buds, the manner of which occurrence is described in the works of ancient writers upon agriculture, and to which it is still pretended mixed species are due, such as the orange de bizarrerie, which partakes of the character of the orange, the lemon, and the citron.

We have great difficulty in conceiving how two half buds, applied the one upon the other, can amalgamate and form one single bud partaking of the nature of the two. I would not dare cite my experience to prove that two different buds united together inserted upon an analogous stock, or even placed in the earth, perish if too much mutilated, or develop, each one separately, its scion.

The ill success of these operations would be only a negative proof, which could not destroy the facts if any existed; but I challenge the gardeners to cite me an example, supported by impartial observations, whose exactness they can guarantee. Moreover, if in presenting me such an example they offer me only such individuals as those I possess, and such as I have seen in Liguria, in Tuscany, and such as are known in France under the name of orange de bizarrerie, I would venture to contradict them respecting it.

The anatomy of the tissue of these individuals would furnish me an irresistible argument. This tissue does not present traces of three buds to whose unions the hybrid is pretended to be due. It shows only a branch which bears at one time, but isolated under distinct leaves, buds of three species and buds which give mixed fruit, without, however, enabling us to recognize in these species of embryos anything announcing this mixture.

I will not speak of those imaginary grafts by. which some have pretended to make branches of the fig, grape, rose, and jasmine grow on orange and lemon stocks. I have several times seen such phenomena in Tuscany and Milan, and confess to have been deceived by them; but having been a long time cheated by those gardeners, who sold at exorbitant prices ridiculous recipes for obtaining these extraordinary unions, and after having lost, by making trial of them, several orange stocks, I finally succeeded in discovering the fraud, and am convinced that these heterogenous unions do not exist in nature. I bought a vase containing an orange stock on which a fig scion seemed to be grafted. As soon as I got possession of it I opened the stock where the fig branch was inserted, and discovered that this stock was hollowed out inside, and that through this hole in the interior the would-be graft found its way to the soil, thus living upon its own root instead of that of the orange tree. This discovery completed my conviction that a difference really exists in the organs of different vegetables as well as in the organs of animals, and that from this difference of organization the difference of products results. I know that in

the vegetable kingdom details escape the observation of the physiologist, and it is extremely difficult to give some of the comparative anatomical appearances of vegetables, but it is for this reason no less true that differences may exist and be as unchangeable as in the animal kingdom. Every species has its determined forms, which may be destroyed but not modified, and whatever the nature of the stock which nourishes the plant, it will always give the product proper to its species.

ART. IV.-Influence of culture and soil on plants. Culture and climate have appeared to many writers more powerful than the graft, and they have attributed to them the very decided changes in the secondary characteristics of trees. It is principally to the force of culture that they attribute the sensible difference existing between the wild and cultivated trees. But it is easy to see that this is a mistake in their judgment, and that they attribute these differences to culture or the graft, merely because these are the processes which always accompany the individuals-which undergo a change and become improved fruit, and because these are the means of multiplying the number of the improved individuals. Whereas these are mere accidents; they have, because constantly used, been considered the causes of the changes in the fruit.

Nature gives some trees which bear ordinary fruit and others which bear fine fruit. The first, always being grafted when in our gardens, bears its own peculiar wild fruit only when found in the woods; and the cultivator who sees them there in a degraded condition concludes that this degeneration is due to the want of cultivation. The trees bearing fine fruit, being seen only in a state of cultivation, and multiplied by the graft only, the cultivator, ignorant of the origin of their ancestors, judges that they owe their improvement to the graft and the culture which they have undergone. I say the cultivator judges in this manner on account of this ignorance of the first original tree which gave these different results which he observes; because there has never existed a writer, to my knowledge, who has carefully noted how one of these changes has occurred. They all speak of the changes and note the difference which exists between those individuals found in the woods and those found in the gardens, but no one has seen this change take place on one and the same individual. I say all see it through the dimness of ages, and their conclusion is the result of conjecture rather than of observation.

But a close and continuous attention to nature will show that these differences, which exist in two distinct individuals, as, for instance, the pear of the forest and the pear of cultivation, never appear successively on the same individual. I call an individual the plant which exists on its own stock, and which enjoys the life given it by Nature, and I also term an individual the collection of all the plants which proceed from a single germ, and consequently form only one single plant, which may be multiplied without changing its character, either by passing successively on to an infinite number of stocks as a graft, or by forming by means of slips an infinite number of stocks

of its own, having a root in the earth, and prolonging in this manner its own life, as well as that of the species, and thus varying infinitely the places and modes of its existence, but always bearing in itself the principles of organization received in its conception.

The individual which perished on the root where it germinated, and that which renews for the millionth time, it may be, its life, in a graft or a slip, have a single and common origin, and hence are one and the same individual. This individual, though infinitely multiplied, will always bear in the numberless subdivisions of its being the same characteristics and the same aspect which it had in the beginning. To illustrate, take the sugar-cane. In India, beyond the Ganges, there are several varieties of this plant which are propagated by seeds, but in San Domingo, where it is reproduced by slips, only one variety is known. It has been cultivated there since 1606, with different methods and a variety of soils, and still remains unchanged. Neither the processes of cultivation nor the difference in soils have improved it in the course of two centuries, and the only reason why it has not degenerated is because it has always been multiplied by cuttings.

This fact is perfectly in harmony with the theory of the manner in which culture affects vegetables. Nutrition is the most powerful means by which they can be influenced in cultivation. The nourishing juices, of which the earth is the principal vehicle, are everywhere of the same nature; chemistry has proved that the same clements unite to form the acorn in the oak tree and the orange in the orange tree. It is in the different organs of the diverse genera of vegetables that these same principles are decomposed, elaborated, and finally acquire forms and properties widely different from each other.

Now, can we suppose, without wounding the principles of sound philosophy, that this passive material, which is designed only to receive modifications from the different agents by which it is elaborated and used-that this can react upon those organs or agents and change their exist ence, a work so marvellous that Nature only can perform it?

It has been held that the multiplicity of petals, which form double flowers, and the certain lusti ness of some varieties are due to a superabundance of nutrition. But this formation of petals is not the simple development of a principle pre-existing in the flower. It is a real change of the male and female parts into corollas; and the lux uriance of these beautiful varieties bears in the leaf and in the fruits new forms, which distinguish them from others and constitute them distinct races.

Nature has fixed for all races a maximum and a minimum of development which no cause can surpass. When a plant has little nutriment it becomes feeble and languishes, but it will die before departing from the characteristics of its species. If well nourished it attains the maximum of its growth, but if engorged it refuses the superabundance, or, if forced to absorb, it is injured; its canals are blocked up, its organs affected, its vital functions changed, and it perishes. The facts we possess are in harmony with these principles. We find double flowers only in species which are multiplied by seed. Those

propagated by slips or the graft never present this phenomenon. We never find it in the jas. mine, the hortensia, nor in any of those exotics which in our climate yield, no sced. But they are certainly cultivated with as much care as roses, hyacinths, or carnations; but they never present the caprices of these beautiful varieties, which reappear every day in our gardens under new forms and with a mixture of the most charm ing colors. The error of these cultivators has been still more extraordinary in regard to sterility of plants, which they have attributed to the mode of propagation by slips or by layers. All these opinions could result only from erroneous reasoning.

We have already seen that--having observed that plots of ground were covered with choice varieties while the woods were full only of wild ones -it was inferred that it was culture which had changed the savage varieties to fine ones, so that these last are now called domesticated varieties. In this case of the sterile plants--having observed that they were multiplied only by the slip and the layer, it has been inferred that it was the mode of propagation which effected in the plant subjected to this operation for several generations, the insensibly gradual loss of its stamens and pistils, and finally produced sterility. Here it is easy to see the effect has been taken for the cause. These plants have been considered sterile because propagated by the cuttings, whereas the contrary is true, and they are propagated by the cuttings because they are themselves sterile; other ise it would follow that all plants multiplied by the slip would be sterile, which is not the case. Examples might be given in abundance of plants bearing fertile seeds, which have long been multiplied by the cuttings, as the olive and the grape; and a great number of superior varieties are produced by the slip only to keep them from degenerating.

But the most conclusive proof of the futility of this belief is the fact that these plants of sterile flowers all have their type, which is not sterile, and whose seeds have probably given the sterile variety which has been multiplied by cuttings. Indeed, we sometimes find this variety in the woods, where nature certainly has used no grafting knife, as, for instance, in the sterile snowball (viburnum opulus sterilis) beside the riburnum opulus or snowball of fruitful flower.

I shall not occupy my time in discussion upon the influence of infusions of sugary substances and other similar processes by which all the ancient writers pretend to change the taste and color of fruits; all these notions are now relegated to the books on agriculture of the seventeenth century, and there is no cultivator, however little enlightened, who is not convinced of their uselessness.

Besides, these errors cannot but disappear from the moment that we are convinced that nutrition (by which means the cultivation of the soil acts upon plants or trees,) influences only their ple developments, but that forms, colors, properties, can only be changed by the seed.

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but the negro transported to the eternal snows of the North will suffer no change any more than will the white man under the burning sun of Africa. The giant will procure his stature amid the most cruel want, and the dwarf will never change his proportions, though supplied with the most nourishing food. Nature has determined the forms of all beings; she has fixed the principles of their organization in the embryo, and nothing can alter them. They resist every force that surrounds them, and ever preserve, amid the continual variation of nourishment and soil, the original impress received from the hand of Nature.

ART. V.—The reproduction of plants by the seed.

The seed is the only source of varieties in vege tables. It is only by this means that nature ef fects those wonderful transformations every day witnessed, but too little understood. The majority of cultivators acknowledge this fact; and even those who attribute beautiful varieties to culture also agree that many are furnished by the seed.

We propose, by the following experiments recorded by a French naturalist of great experi ence, to show the results of reproduction by seed.

seeds of the china orange (citrus aurantium si Experiment I-I sowed, during several years, nense), of a fine shining skin. I always obtained sweet orange trees, of which a part bore oranges of a thick, rough skin, and a part beautiful fruit of a skin still finer than the original which furnished the seed. The same thing occurred in the sowing of ordinary oranges of thick and rough skin-there grew up several trees of beautiful fruit, and one stock, whose leaves were like shells in shape, but the fruit very ordinary and seeds few, and even those very poor.

I made the same experiment with the peach tree; seeds from peaches borne on the same tree gave several varieties, for the most part of ordinary fruit, but a few finer than the original planted; but the stones never gave a cling-stone peach, nor a cling-stone the ordinary fruit.

The almond gave the same result. Sweet almonds produced only sweet almond trees. There was some difference in the hardness of the shell, but I never obtained a single bitter almond.

Experiment II-I sowed seeds of the red orange (citrus aurantium sinense, hierochunticum, fructu sanguineo). The trees which came from these produced only ordinary fruit of orange color.

Experiment III.-I sowed lemon seeds taken from truit gathered in a garden where lemon and citron trees grew together, and obtained many trees, whose fruit presented a series of varieties, from the lemon to the poncire, but the larger part of them were simple lemons. Those having the characteristics of the poncire produced no seeds.

Experiment IV-During a long series of years I sowed seeds of the sweet orange, sometimes taken from seedlings, sometimes from seedlings sim-grafted on a sour orange stock or a lemon stock, but always obtained sweet oranges. This result is confirmed by all the gardeners of Finale (a small town in the north of Italy) for more than sixty years. There is no example of a sour orange produced from a sweet seed, nor of a sweet orange produced from a sour seed.

Such is the march of nature in all the chain of organized beings. Generations vary infinitely, but individuals never change. The negro and the white man give rise to numerous mulattoes,

From these experiments are obtained the following conclusions:

Consequence I.-The seed perpetuates the species and is the source of varieties. It produces moré frequently varieties inferior to the mother plant; sometimes, however, those superior to it. It never departs from the species unless the fecundation of another species gives it the germ of a hybrid. (Exp. I and III.) This occurs equally in the seed of the seedling and that of the grafted tree. The trees which come from them reproduce the same species which gave the seed, aside from the modification of varieties noticed above. (Exp. IV.)

Consequence H.-The seeds of monsters, when they are found, produce only ordinary fruit, which indicates that this extraordinary fruit is only a variety, and that the variety returns to the type in the seed. (Exp. II.)

Consequence III.-The seeds of the sweet orange produce only sweet orange trees; sour orange seeds produce only sour orange trees. These two orange trees are preserved and perpetuated by the seed, and are, therefore, distinct species. The ordinary peach never produces the cling stone, nor the cling-stone the ordinary peach, and hence they are two distinct species, and can not degenerate from the one to the other. The

same is true of the sweet and bitter almond. (Exp. I and IV.)

Consequence IV.-The seeds of lemons growing in a garden where lemon and citron trees grew together, produced poncires. This fruit is, therefore, probably a hybrid of the citron, the absence of seeds showing that it is due to a foreign fecundation. (Exp. III.)

ART. VI.-The theory of vegetable reproduction. My experiences as a whole sufficiently substantiated the most of the phenomena presented by the multiplication from seed. They deterniined the origin of varieties in plants. But it remained still to know the secret causes of these results-why nature departed in some cases from the system generally followed in reproduction. Every seed in nature is only the germ which is to renew the individual which produced it; but some vegetables we have seen depart from this system.

What is the cause of these exceptions? I observed that these phenomena took place from preference in the seeds taken from plantations where there was a mixture of species or varieties; that lemons gathered in the garden where there were citrons gave more varieties than those from trees standing alone; that the seed of the black cabbage which had flowered in the midst of many cabbages of different varieties, produced frequently cabbage remarkably well headed, much sought for its delicacy and whiteness; that the seed of the crowfoot of several colors, which I cultivated in quantity in plots of my garden, gave very often double flowers, while this did not happen with the seeds of the same flowers which I had cultivated in vases, each by itself, before the establishment of my flower garden.

All these observations presented a certain analogy between the hybrids and the monsters, and I suspected that the influence of the pollen which effected the mixture in hybrids might also cause

sterility, and those modifications of leaf known as curled or streaked.

A crowd of reflections were presented to my mind. It is recognized, I reasoned, that two dif ferent principles must co-operate for the reproduction of all organized beings. We know that when these principles belong to different species monstrosities result, such as mules among animals, and among vegetables the mixed plants known under the name of hybrids.

Why may not this principle, which effects so many phenomena, be the cause of monsters and varieties? These, it is true, do not prove the seed of isolated trees; but is it nccessary that mixture, for they are produced even from the the principles of two different species unite in fecundation in order to change the physiognomy of the product? Cannot this be as well accomin the same species, and perhaps also by a differ plished by different properties of the two agents ence in the force of their action, or by a defect in the analogy in their principles? Is it not from the different proportion of these two agents of organic reproduction, that results this marvelous variety, distinguishing all animals by a peculiar physiognomy? There is no fruit in the same plant even which is exactly like any other.

Might not the inequality which exists among the fruits of a single tree, as we observe it among the children of the same father, exist still more pronounced between the fruits of two different plants, although of the same species? Should not the pollen of the flower of one peach tree have a family likeness which would make it different from that of the flower of another peach tree, and if these two peach trees, modified in their conception by fecundation, were already marked by those differences which constitute varieties, would not the reunion of their flowers produce a new combination which would constitute a variety still more irregular? Finally, what might not the difference in the proportions and the mixture of several pollens produce? Would not a forced fecundation act upon the ovary in an extraordinary manner, and changing the natural relations of the principles, form heterogeneous combinations incapable of bearing sexual organs?

All these queries were presented to my mind in a manner so favorable and seductive that I made no delay in preparing experiments to throw light upon them. Their results have been so satisfactory that I have been able to draw therefrom a theory which has served as the basis of my classification of orange trees. I shall give an explanation of them.

ART. VII.-Erperiments in artificial fecundation.

Experiment V-I chose a number of plants of the Asiatic, ranunculus, of simple flower, and of different colors. I put each one in a vase, and placed them in as many different windows, separated from each other. I fecundated the flowers of one-half these plants with the pollen of each other, but left the other half undisturbed. The following results were obtained: The seeds of the flowers fecundated as aforestated produced roots of which some gave double flowers, others semi-double, and the greater part only single flowers. The plants not fecundated gave only

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