Constitution (biology)

“ So that while these units have a general proclivity towards the structure of the organism as a whole, they have also proclivities towards structures proper to the local conditions into which they fall. There is latent in each unit the constitution of the entire organism and by implication the constitution of every organ; and each unit while co-operating with the aggregate is ready to take part in that particular arrangement proper to the position it has fallen into. ”

“ Resting upon the law of the division of physiological work, the importance of which was first demonstrated by Milne-Edwards, and upon that of polymorphism, which without it have only a limited and indefinite meaning, consequent on the law of division of protoplasmic masses, it has been the great producer of organization, and establishes a new link between sociology and the branches of biology that are occupied with the constitution and functions of organisms. ”

“ No sooner are the lambs weaned than their strength, their vigour, and their beauty begin to decay.... At last the constitution gives way ... he remains stunted for life:" the constitution being thus proved unstable or unadapted to the requirements. ”

“ Thus the law of "natural selection," instead of dispensing with anterior causation and enabling the animal races to be their own Providence and do all their own work, distinctly testifies to a constitution of the world pre-arranged for progress, externally spread with large choice of conditions, and with internal provisions for seizing and realizing the best. ”

“ But be this latter point accepted or rejected, the one point which admits of no dispute is that an organism is radically distinguishable from every inorganic mechanism in that it acquires through the very exercise of its primary constitution, a new constitution with new powers. ”

“ No matter how many generations of organisms there may have been, and therefore no matter how many combinations of germ-plasm may have taken place to give rise to an existing population, each existing unit of germ-plasm must have remained of the same essential nature or constitution as when it was first started in its immortal career millions of years ago. ”

“ Similarly in each species of higher animal, development of the reproductive organs and maturation of reproductive cells take place at a settled age, whether the conditions have {300}been favourable or unfavourable to physical prosperity. The established constitutional tendency, adapted to the needs of the species, over-rides the constitutional needs of the individual. ”

“ Now we have to remember that species, living and extinct, are numbered by millions, and represent every variety of type, constitution, and habits; is it probable, then, that this one peculiarity of the reproductive system should be due, in so many cases, to some merely incidental effect produced on that system by uniform conditions of life? ”

“ Thus the principle of natural selection is THE SELECTION OF THE BEST FOR REPRODUCTION, whether the "best" refers to the whole constitution, to one or more parts of the organism, or to one or more stages of development. Every organ, every part, every character of an animal, fertility and intelligence included, must be improved in this manner, and be gradually brought up in the course of generations to its highest attainable state of perfection. ”

“ Certain preliminary conditions are obviously requisite; in the first place there must be a sound constitution derived from healthy ancestors, and in the second there must be a freedom from organic disease of important organs. ”

“ No doubt in every case there must have been some exciting cause; but as we see innumerable individuals exposed to nearly the same conditions, and one alone is affected, we may conclude that the constitution of the individual is of far higher importance than the conditions to which it has been exposed. ”

“ Just as every species by its natural rate of reproduction would soon completely fill any country it could live in, but does not, being checked by some other species or some other condition—so it may be surmised that variation and natural selection have their struggle and consequent check, or are limited by something inherent in the constitution of organic beings. ”

“ Most probably we shall find the solution of such conditions to exist within the operation of some deep-seated law of the living constitution, and in the effects of that law in molding, or even contorting, the animal frame. ”

“ I am so little disposed to speak in favour of an unknown transforming power that I may here again insist that the transformation of a species only partly depends upon external influences, and partly on the specific constitution of the particular form. I designate this constitution ‘specific,’ inasmuch as it responds to the same inciting cause in a manner different to the constitution of another species. ”

“ Professor Dendy also holds that the law of recapitulation, which may be stated thus, that the life-history of the individual is a recapitulation of the life-history of the race, is a logical necessity if evolution has taken place. Leaving out, for the present, the complication introduced by the union of two germ cells of separate sexes, the behaviour of the germ cell during development is conditioned by two factors, namely its own constitution and its environment. ”

“ Any biological law which epitomizes only facts about the lower creatures is not a general biological law, for general biological laws must take account not only of plants and animals, but of man as well. ”

“ Under nature it seems improbable that the differences in the reproductive constitution, on which the sterility of any two species when crossed depends, can be acquired directly by Natural Selection; for it is of no advantage to the species. Such differences in reproductive constitution must stand in correlation with some other differences ”

“ A sound original constitution may be regarded as the first condition of the healthy action of the brain; for, being a part of the animal economy, it is subject to the same general laws that govern the other bodily organs. ”

“ In most higher animals progress is brought about chiefly by natural selection operating upon individuals, although in a few forms selection operates chiefly upon groups of communities: in both cases the changes in the inherited constitution of the species are the important changes. In man, however, in all except the very early stages of his development, changes in inherited constitution have been small and unimportant, and the chief changes of evolutionary significance have been those in tradition ”

“ The law which we have thus traced throughout the {601}animal kingdom, and which must alike determine the different fertilities of different species, and the variations of fertility in the same species, we have now to consider in its application to mankind. ”

“ The constitution of sanguineous animals, so far as the parts as yet mentioned are concerned, and the reasons for such constitution, have now been set forth. In natural sequence we should next go on to the organs of generation, as yet undescribed, on which depend the distinctions of male and female. ”

“ In most, perhaps in all cases, the organisation or constitution of the being which is acted on, is a much more important element than the nature of the changed conditions, in determining the nature of the variation. ”

“ The proofs that are relied upon to establish the operation and effect of these agencies in producing the results that are claimed for them, ought to show that, in one or more instances, an animal of a superior organization which, when left to the natural course of its reproduction by the union of its two sexes, always produces its own distinct type and no other, has, in fact, been itself evolved out of some lower and different organism by the agencies of natural and sexual selection operating among the individuals of that lower type. ”

“ Impossible though it may be to imagine the natures of those ultimate units peculiar to each species, which have proclivities towards the particular form of organization characterizing it, yet that a change of structure arising in one part of the organism is accompanied by multitudinous changes of structure in other parts of the organism, is not only congruous with the belief that there exist such constitutional units, but yields it distinct support. ”

“ We have seen reason to think that, as fast as essential faculties multiply, and as fast as the number of organs that co-operate in any given function increases, indirect equilibration through natural selection becomes less and less capable of producing specific adaptations; and remains fully capable only of maintaining the general fitness of constitution to conditions. ”

“ We must demand of it a verdict upon doctrines respecting the constitution of the living individual and its origin and the constitution of the species to which the individual belongs, which verdict shall oblige us to accept these doctrines as corollaries of the same general principles from which the accepted theories of the other abstract sciences are likewise deduced. ”

“ And besides that, I could by no means see what the explanation explained. Neither did it help me to be told by an eminent anatomist that species had succeeded one another in time, in virtue of "a continuously operative creational law." That seemed to me to be no more than saying that species had succeeded one another in the form of a vote-catching resolution, with "law" to catch the man of science, and "creational" to draw the orthodox. ”

“ What we ask, and rightly ask, is whether in the laws of biological progress we can find any principle which we can apply directly to guide us in devising methods for human progress.
I do not propose to follow the example of many rather hasty philosophers and biologists, who have thought that, whenever the study of lower organisms permitted the promulgation of a biological law, such law can be lifted bodily from its context and be applied without modification to human affairs. Man is an organism—but a very exceptional and peculiar organism. ”

“ Suppose I invert the idea and say that the organ is maintained at its right size by natural selection, because this prevents increase beyond the size which is best for the organism. Every organ should be in due proportion, and the welfare of the creature as a whole is interfered with by excess as well as by defect. ”

“ And yet it is difficult to say this if Biology is to be considered as the law of actions of organisms. It all depends upon the factors which are included in the generalisation. If the factors are simply physical, then the generalisation is insufficient; if the forces included in the moving equilibrium include subjective forces capable of growth into sympathy or Altruism, then the biological laws receive, perhaps, an extension which renders them capable of determining the whole of the phenomena. ”

“ The most important of these, or the one that most interests us in the present connection, is the law of natural selection; and it must be that germs, in common with other forms of life, are under the influence of this law in some shape. Natural selection is a general term which embraces all other modes of selection, or provision for the "survival of the fittest." ”

“ If your large knowledge of geographical distribution should enable you to supply me with specific cases of the general principle mentioned by Darwin in the quotation given on page 392 ('Origin of Species,' 6th ed., pp. 134-5) , I should much like to try experiments on the sterility which I should expect to find between these interlocking species.
It seems comical to ask a scientific opponent for assistance, but the fact of being able to do so proves the superiority of science to politics. ”

“ Thus we get proof that relatively pure constitutions predominate in progeny over much mixed constitutions. The reason is not difficult to see. Every organism tends to become adapted to its conditions of life; and all the structures of a species, accustomed through multitudinous generations to the climate, food, and various influences of its locality, are moulded into harmonious co-operation favourable to life in that locality: the result being that in the development of each young individual, the tendencies conspire to produce the fit organization. ”

“ And as it is not likely that man should have succeeded in selecting so many breeds and sub-breeds with constitutions specially fitted for their own districts, the result must, I think, be due to habit. On the other hand, natural selection would inevitably tend to preserve those individuals which were born with constitutions best adapted to any country which they inhabited. ”

“ But a decisive objection, founded on the most positive data of sociology, can be raised against the jury.
The law of natural evolution proves that no variation in the vegetable or animal organism is useful or durable which is not the outcome of a slow and gradual preparation by organic forces and external conditions. Thus an organ which ceases to have a function to discharge is subject to atrophy, and no new organ is possible or capable of development if it is not required by a new function to which it corresponds. ”

“ A very similar mode of reasoning will apply to the other branch of the subject—the initiation of structures and organs by the action of the fundamental laws of growth. Admitting that such laws have determined some of the main divisions of the animal and vegetable kingdom, have originated certain important organs, and have been the fundamental cause of certain lines of development, yet at every step of the process these laws must have acted in entire subordination to the law of natural selection. ”

“ But when, from the nature of the organism and of the conditions, modifications have been induced which are unimportant for the welfare of the species, they may be, and apparently often have been, transmitted in nearly the same state to numerous, otherwise modified, descendants. ”