Nectary is a pit in each petal above the claw. Stam. Filaments very numerous, shorter by half than the corol. Anthers erect, oblong, obtuse, twin. Pist. Germs numerous, collected in a head. Styles none. Stigmas reflected, very small. Per. none. Receptacle annexing the seeds with very minute peduncles. Seeds very numerous, irregular, uncertain in figure, naked, with a reflected top. NEW THEORIES OF EVOLUTION: LAMARCK THE piling up of facts and their assorting brought the need for a fresh philosophy of evolution. Among several writers, perhaps the most interesting was Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck, who was born in Picardy in 1744, the eleventh child of a poor landowner. At the age of 17, he ran away from the Jesuits' college at Amiens to take part in the Dutch wars, but soon had to leave the army owing to ill health. He studied medicine in Paris, supporting himself by working in a bank, and won fame by his botanical writings. Appointed to a zoological professorship, he extended his studies to animals, and although blind in his later years, published important works on the classification of Invertebrata, etc. He died in poverty in 1829. His claim to attention here rests on his recognition of the mutual relations and variability of species-in common with other thinkers of his ageand on his theory of the formation and modification of organs by habit-a gallant and plausible attempt to explain how evolution might have occurred. Many have since tried to reproduce such modifications experimentally, but a proof of the inheritance of acquired characters is still lacking. PHILOSOPHIE ZOOLOGIQUE. LAMARCK (Translation taken from Zoological Philosophy, by Hugh S. Elliot, 1914.) CHAP. III. Of species among living bodies. It is not a futile purpose to decide definitely what we mean by the so-called species among living bodies, and to inquire if it is true that species are of absolute constancy, as old as nature, and have all existed from the beginning just as we see them to-day; or if, as a result of changes in their environment, albeit extremely slow, they have not in course of time changed their characters and shape.... Let us first see what is meant by the name of species. Any collection of like individuals which were produced by others similar to themselves is called a species. This definition is exact; for every individual possessing life always resembles very closely those from which it sprang; but to this definition is added the allegation that the individuals composing a species never vary in their specific characters, and consequently that species have an absolute constancy in nature. It is just this allegation that I propose to attack, since clear proofs drawn from observation show that it is ill-founded. The almost universally received belief is that living bodies constitute species distinguished from one another by unchangeable characteristics, and that the existence of these species is as old as nature herself. This belief became established at a time when no sufficient observations had been taken, and when natural science was still almost negligible. It is continually being discredited for those who have seen much, who have long watched nature, and who have consulted with profit the rich collections of our museums. Moreover, all those who are much occupied with the study of natural history, know that naturalists now find it extremely difficult to decide what objects should be regarded as species. They are in fact not aware that species have really only a constancy relative to the duration of the conditions in which are placed the individuals composing it; nor that some of these individuals have varied, and constitute races which shade gradually into some other neighbouring species.... I do not mean that existing animals form a very simple series, regularly graded throughout; but I do mean that they form a branching series, irregularly graded and free from discontinuity, or at least once free from it. For it is alleged that there is now occasional discontinuity, owing to some species having been lost. It follows that the species terminating each branch of the general series are connected on one side at least with other neighbouring species which merge into them. This I am now able to prove by means of well-known facts. I require no hypothesis or supposition; I call all observing naturalists to witness. Not only many genera but entire orders, and sometimes even classes, furnish instances of almost complete portions of the series which I have just indicated. When in these cases the species have been arranged in series, and are all properly placed according to their natural affinities, if you choose one, one, and then, jumping over several others, take another a little way off, these two species when compared will exhibit great differences. It is thus in the first instance that we began to see such of nature's productions as lay nearest to us. Generic and specific differences were then quite easy to establish; but now that our collections are very rich, if you follow the above-mentioned series from the first species chosen to the second, which is very different from it, you reach it by slow gradations without having observed any noticeable distinctions. I ask, where is the experienced zoologist or botanist who is not convinced of the truth of what I state?... To assist us to a judgment as to whether the idea of species has any real foundation, let us revert to the principles already set forth; they show (1) That all the organised bodies of our earth are true productions of nature, wrought successively throughout long periods of time. (2) That in her procedure, nature began and still begins by fashioning the simplest of organised bodies, and that it is these alone which she fashions immediately, that is to say, only the rudiments of organisation indicated in the term spontaneous generation. (3) That, since the rudiments of the animal and plant were fashioned in suitable places and conditions, the properties of a commencing life and established organic movement necessarily caused a gradual development of the organs, and in course of time produced diversity in them as in the limbs. (4) That the property of growth is inherent in every part of the organised body, from the earliest manifestations of life; and then gave rise to different kinds of multiplication and reproduction, so that the increase of complexity of organisation, and of the shape and variety of the parts, has been preserved. (5) That with the help of time, of conditions that necessarily were favourable, of the changes successively undergone by every part of the earth's surface, and, finally, of the power of new conditions and habits to modify the organs of living bodies, all those which now exist have imperceptibly been fashioned such as we see them. (6) That, finally, in this state of affairs every living body underwent greater or smaller changes in its organisation and parts; so that what we call species were imperceptibly fashioned among them one after another and have only a relative constancy, and are not as old as nature.... CHAPTER VII. Of the influence of the environment on the activities and habits of animals, and the influence of the activities and habits of these living bodies in modifying their organisation and structure. We are not here concerned with an argument, but with the application of a positive fact—a fact which is of more general application than is supposed, and which has not received the attention that it deserves, no doubt because it is usually very difficult to recognise. This fact consists in the influence that is exerted by the environment on the various living bodies exposed to it.... If we had not had many opportunities of clearly recognising the result of this influence on certain living bodies that we have transported into an environment altogether new and very different from that in which they were previously placed, and if we had not seen the resulting effects and alterations take place almost under our very eyes, the important fact in question would have remained for ever unknown to us. The influence of the environment as a matter of fact is in all times and places operative on living bodies; but what makes this influence difficult to perceive is that its effects only become perceptible or recognisable (especially in animals) after a long period of time.... I must now explain what I mean by this statement: the environment affects the shape and organisation of animals....It is true if this statement were to be taken literally, I should be convicted of an error; for, whatever the environment may do, it does not work any direct modification whatever in the shape and organisation of animals. But great alterations in the environment of animals lead to great alterations in their needs, and these alterations in their needs necessarily lead to others in their activities. Now if the new needs become permanent, the animals then adopt new habits which last as long as the needs that evoked them. This is easy to demonstrate, and indeed requires no amplification.... Now, if a new environment, which has become permanent for some race of animals, induces new habits in these animals, that is to say, leads them to new activities which become habitual, the result will be the use of some one part in preference to some other part, and in some cases the total disuse of some part no longer necessary. Nothing of all this can be considered as hypothesis or private opinion; on the contrary, they are truths which, in order to be made clear, only require attention and the observation of facts. We shall shortly see by the citation of known facts in evidence, in the first place, that new needs which establish a necessity for some part really bring about the existence of that part, as a result of efforts; and that subsequently its continued use gradually strengthens, develops and finally greatly enlarges it; in the second place, we shall see that in some cases, when the new environment and the new needs have together destroyed the utility of some part, the total disuse of that part has resulted in its gradually ceasing to share in the development of the other parts of the animal; it shrinks and wastes little by little, and ultimately, when there has been total disuse for a long period, the part in question ends by disappearing. All this is positive; I purpose to furnish the most convincing proofs of it.... Naturalists have remarked that the structure of animals is always in perfect adaptation to their functions, and have inferred that the shape and condition of their parts have determined the use of them. Now this is a mistake: for it may easily be proved by observation that it is on the contrary the needs and uses of the parts which have caused the development of these same parts, which have even given birth to them when they did not exist, and which consequently have given rise to the condition that we find in each animal. |