guesses. The inverse square was the only one which caused calculation to agree with observation; the inverse square was therefore assumed to be the true law. The most complicated calculations were based upon this assumption; they have been carefully corroborated by observation, and in this manner the law of gravitation has been proved true beyond all dispute. Those who attack the philosophic method of Mr. Darwin ought explicitly to state how they would proceed to establish a theory on the origin of species by what they term a rigorous induction. Is such an example to be found in the doctrine of creative fiats? The greatest of logicians has remarked, "The mode of investigation which, from "the proved inapplicability of direct "methods of observation and experi"ment, remains to us as the main source "of the knowledge we possess, or can "acquire, respecting the conditions and "laws of recurrence of the more complex "phenomena, is called in its most gene"ral expression the deductive method, "and consists of three operations-the "first, one of direct induction; the "second, of ratiocination; and the third, " of verification." The method here indicated Mr. Darwin has most rigorously observed. A life devoted to the most careful scientific observations and experiments, and to the accumulation of a most comprehensive knowledge of the details of natural history, has suggested to Mr. Darwin's mind a certain hypothesis with regard to the origin of species. The results which have been deduced from this hypothesis he has endeavoured to verify by a comparison with observed phenomena. Mr. Darwin has been himself most careful to point out that this verification is not yet complete. Until it becomes so, Mr. Darwin's theory must be ranked as an hypothesis. The eminently high authorities who have already welcomed Mr. Darwin's theory as a probable hypothesis, should induce the general public to welcome it as a legitimate step towards a great scientific discovery; and those who cannot take any

special part in the controversy will render science a great service if they resent bigoted prejudice, and earnestly seek to give both parties in the dispute a fair hearing.

It has been previously remarked that every species is composed of individuals, which are grouped into varieties, these varieties being distinguished from each other by a varying amount of difference. For instance, all the breeds of dogs are varieties of the same species. The characteristic points of these breeds strike the most casual observer. There is the utmost diversity in size; the heads vary in form, the coats in colour and texture, the legs in length; and animals varying in these respects inherit also different constitutions and different capabilities. But all these breeds are considered to belong to the same species, because each variety of dog is perfectly fertile with every other. Now that it is found that a fertile cross can be with facility obtained between the wolf and the dog, these animals are classed in the same species. A less difference may very reasonably be thought to exist between the horse and the ass than between the poodle and the mastiff; but the mule, which is the offspring of the horse and the ass, is sterile, and therefore these animals are regarded as distinct species. The various breeds of dogs have been produced by a method with which, as applied to the varieties of other species, every agriculturist and gardener is perfectly familiar. Mr. Darwin supposes that a similar method is at work throughout the whole range of animated nature. He has himself for years made most careful experiments upon the breeding of pigeons, and the art may be thus explained :-Suppose a breeder is anxious to produce pigeons with some particular characteristic, for instance, a short beak. It is a law which is always in operation, but which, at the same time, cannot be explained, that the offspring of the same parents possess some individual differences. The most casual observer must have remarked the many points of difference which the same litter of pups

pigeons, the offspring of the same parents, are minutely examined, it will be invariably found that there are already existing some slight points of diversity in the particular organ which it is sought still further to modify. If the object, therefore, is to produce short beaks, those young pigeons must be selected which have the shortest beaks. Another universal but still inexplicable law can be enunciated, that individual peculiarities are inheritable, and thus the young pigeons, which are bred from those which have been previously selected for their short beaks, will, on the average, possess shorter beaks than those which have been bred from unselected parents. A second selection is now made. The shortest-beaked birds are again reserved; and thus at last, by continuing the process, these small differences will be constantly accumulated, until at length the shortened beak becomes a decided characteristic, and a new breed or variety will have been thus established. In this manner all our breeds of domestic animals and all our varieties of plants and flowers might have been produced. Thus a gardener may have raised a plot of seedling geraniums from seed all taken from the same plant. The flowers and leaves of these seedling geraniums will in all probability present some points of difference in colour and size. It may be the gardener's object to produce a flower of some particular colour. Amongst his seedlings he selects those which approach most nearly to this colour. Very possibly out of many hundreds he may find very few which offer a sufficient approximation. Let us suppose that he has selected two. As plants are more prolific when not fertilized with their own pollen, he fertilizes one of these geraniums with the pollen of the other. Amongst the geraniums which are raised from this seed, only a few will probably possess any tendency towards the colour which it is sought to produce. Those which exhibit the strongest tendency towards this colour are again preserved; the process is again repeated, until at length the skill of the gardener is rewarded, the

variety of geranium is the result. Then there will be no difficulty in perpetuating this variety by means of cuttings, which always produce plants true to the one from which they have been taken. And thus the horticulturists and the breeders of animals avail themselves of two universal laws of nature, which are—

1st. The constant tendency towards individual variations.

2dly. The constant tendency to inherit individual peculiarities.

These resources are supplied to man in the original constitution of organic life, and enable varieties to be produced when the selection is directed by man's intelligence. In nature, a selection cannot be thus directed. Is there, therefore, in nature any such selection regulated by fixed laws? Mr. Darwin maintains that this power of selection is supplied by the struggle for life; and the main fundamental object of his theory is, to show that this struggle for existence is ever at work, constantly tending to produce and to perpetuate, by definite laws, varieties of organisms no less distinct and decided than those which man creates amongst domesticated animals and cultivated plants.

There are those who dispute whether the struggle for existence is capable of effecting all that Mr. Darwin attributes to it; but the reality of this struggle for existence throughout the whole of nature is a demonstrated truth. Mr. Darwin remarks: "This struggle "for existence inevitably follows from "the high geometrical ratio of the in"crease of all organic beings throughout "the world." This is the doctrine of Malthus applied to the whole animal and vegetable kingdoms. The mention of Mr. Malthus will, we fear, not induce conviction; for our leading public journal, no doubt very accurately, re-echoed the popular ignorance and prejudice with regard to Mr. Malthus, when he was lately described as that "morose, "hard-hearted old man, whose theories "now are entirely exploded." But the intensity of the struggle for existence, necessitated by the laws of propagation

guesses. The inverse square was the only one which caused calculation to agree with observation; the inverse square was therefore assumed to be the true law. The most complicated calculations were based upon this assumption; they have been carefully corroborated by observation, and in this manner the law of gravitation has been proved true beyond all dispute. Those who attack the philosophic method of Mr. Darwin ought explicitly to state how they would proceed to establish a theory on the origin of species by what they term a rigorous induction. Is such an example to be found in the doctrine of creative fiats ? The greatest of logicians has remarked,1 "The mode of investigation which, from "the proved inapplicability of direct "methods of observation and experi"ment, remains to us as the main source "of the knowledge we possess, or can "acquire, respecting the conditions and "laws of recurrence of the more complex

phenomena, is called in its most gene"ral expression the deductive method, "and consists of three operations-the "first, one of direct induction; the "second, of ratiocination; and the third, " of verification." The method here indicated Mr. Darwin has most rigorously observed. A life devoted to the most careful scientific observations and experiments, and to the accumulation of a most comprehensive knowledge of the details of natural history, has suggested to Mr. Darwin's mind a certain hypothesis with regard to the origin of species. The results which have been deduced from this hypothesis he has endeavoured to verify by a comparison with observed phenomena. Mr. Darwin has been himself most careful to point out that this verification is not yet complete. Until it becomes so, Mr. Darwin's theory must be ranked as an hypothesis. The eminently high authorities who have already welcomed Mr. Darwin's theory as a probable hypothesis, should induce the general public to welcome it as a legitimate step towards a great scientific discovery; and those who cannot take any

special part in the controversy will render science a great service if they resent bigoted prejudice, and earnestly seek to give both parties in the dispute a fair hearing.

It has been previously remarked that every species is composed of individuals, which are grouped into varieties, these varieties being distinguished from each other by a varying amount of difference. For instance, all the breeds of dogs are varieties of the same species. The characteristic points of these breeds strike the most casual observer. There is the utmost diversity in size; the heads vary in form, the coats in colour and texture, the legs in length; and animals varying in these respects inherit also different constitutions and different capabilities. But all these breeds are considered to belong to the same species, because each variety of dog is perfectly fertile with every other. Now that it is found that a fertile cross can be with facility obtained between the wolf and the dog, these animals are classed in the same species. A less difference may very reasonably be thought to exist between the horse and the ass than between the poodle and the mastiff; but the mule, which is the offspring of the horse and the ass, is sterile, and therefore these animals are regarded as distinct species. The various breeds of dogs have been produced by a method with which, as applied to the varieties of other species, every agriculturist and gardener is perfectly familiar. Mr. Darwin supposes that a similar method is at work throughout the whole range of animated nature. He has himself for years made most careful experiments upon the breeding of pigeons, and the art may be thus explained :-Suppose a breeder is anxious to produce pigeons with some particular characteristic, for instance, a short beak. It is a law which is always in operation, but which, at the same time, cannot be explained, that the offspring of the same parents possess some individual differences. The most casual observer must have remarked the many points of difference which the same litter of pups

pigeons, the offspring of the same parents, are minutely examined, it will be invariably found that there are already existing some slight points of diversity in the particular organ which it is sought still further to modify. If the object, therefore, is to produce short beaks, those young pigeons must be selected which have the shortest beaks. Another universal but still inexplicable law can be enunciated, that individual peculiarities are inheritable, and thus the young pigeons, which are bred from those which have been previously selected for their short beaks, will, on the average, possess shorter beaks than those which have been bred from unselected parents. A second selection is now made. The shortest-beaked birds are again reserved; and thus at last, by continuing the process, these small differences will be constantly accumulated, until at length the shortened beak becomes a decided characteristic, and a new breed or variety will have been thus established. In this manner all our breeds of domestic animals and all our varieties of plants and flowers might have been produced. Thus a gardener may have raised a plot of seedling geraniums from seed all taken from the same plant. The flowers and leaves of these seedling geraniums will in all probability present some points of difference in colour and size. It may be the gardener's object to produce a flower of some particular colour. Amongst his seedlings he selects those which approach most nearly to this colour. Very possibly out of many hundreds he may find very few which offer a sufficient approximation. Let us suppose that he has selected two. As plants are more prolific when not fertilized with their own pollen, he fertilizes one of these geraniums with the pollen of the other. Amongst the geraniums which are raised from this seed, only a few will probably possess any tendency towards the colour which it is sought to produce. Those which exhibit the strongest tendency towards this colour are again preserved; the process is again repeated, until at length the skill of the gardener is rewarded, the

variety of geranium is the result. Then there will be no difficulty in perpetuating this variety by means of cuttings, which always produce plants true to the one from which they have been taken. And thus the horticulturists and the breeders of animals avail themselves of two universal laws of nature, which are

1st. The constant tendency towards individual variations.

2dly. The constant tendency to inherit individual peculiarities.

These resources are supplied to man in the original constitution of organic life, and enable varieties to be produced when the selection is directed by man's intelligence. In nature, a selection cannot be thus directed. Is there, therefore, in nature any such selection regulated by fixed laws? Mr. Darwin maintains that this power of selection is supplied by the struggle for life; and the main fundamental object of his theory is, to show that this struggle for existence is ever at work, constantly tending to produce and to perpetuate, by definite laws, varieties of organisms no less distinct and decided than those which man creates amongst domesticated animals and cultivated plants.

66

There are those who dispute whether the struggle for existence is capable of effecting all that Mr. Darwin attributes to it; but the reality of this struggle for existence throughout the whole of nature is a demonstrated truth. Mr. Darwin remarks: "This struggle "for existence inevitably follows from "the high geometrical ratio of the increase of all organic beings throughout "the world." This is the doctrine of Malthus applied to the whole animal and vegetable kingdoms. The mention of Mr. Malthus will, we fear, not induce conviction; for our leading public journal, no doubt very accurately, re-echoed the popular ignorance and prejudice with regard to Mr. Malthus, when he was lately described as that "morose, "hard-hearted old man, whose theories now are entirely exploded." But the intensity of the struggle for existence, necessitated by the laws of propagation