the improvements which the practice has received since its first introduction into this country, it not very infrequently produces deformity of the skin, and sometimes, under the best management, proves fatal.

These circumstances must naturally create in every instance some degree of painful solicitude for its consequences. But as I have never known fatal effects arise from the Cow-pox, even when impressed in the most unfavourable manner, producing extensive inflammations and suppurations on the hands; and as it clearly appears that this disease leaves the constitution in a state of perfect security from the infection of the Small-pox, may we not infer that a mode of inoculation may be introduced preferable to that at present adopted, especially among those families which, from previous circumstances, we may judge to be predisposed to have the disease unfavourably? It is an excess in the number of pustules which we chiefly dread in the Small-pox; but, in the Cow-pox, no pustules appear, nor does it seem possible for the contagious matter to produce the disease from effluvia, or by any other means than contact, and that probably not simply between the virus and the cuticle; so that a single individual in a family might at any time receive it without the risk of infecting the rest, or of spreading a distemper that fills a country with terror.

[Several instances have come under my observation which justify the assertion that the disease cannot be propagated by effluvia. The first boy whom I inoculated with the matter of Cow-pox slept in a bed while the experiment was going forward, with two children who had never gone through either that disease or the Small-pox, without infecting either of them.

A young woman who had the Cow-pox to a great extent, several sores which maturated having appeared on the hands and wrists, slept in the same bed with a fellow-dairymaid who never had been infected with either the Cow-pox or the Small-pox, but no indisposition followed.

Another instance has occurred of a young woman on whose hands were several large suppurations from the Cow-pox, who was at the same time a daily nurse to an infant, but the complaint was not communicated to the child.]

In some other points of view the inoculation of this disease appears preferable to the variolous inoculation.

In constitutions predisposed to scrofula, how frequently we see the inoculated Small-pox rouse into activity that distressful malady. This circumstance does not seem to depend on the manner in which the distemper has shown itself, for it has as frequently happened among those who have had it mildly, as when it has appeared in the contrary way. There are many, who from some peculiarity in the habit resist the common effects of variolous matter inserted into the

skin, and who are in consequence haunted through life with the distressing idea of being insecure from subsequent infection. A ready mode of dissipating anxiety originating from such a cause must now appear obvious. And, as we have seen that the constitution may at any time be made to feel the febrile attack of Cow-pox, might it not, in many chronic diseases, be introduced into the system, with the probability of affording relief, upon well-known physiological principles?

Although I say the system may at any time be made to feel the febrile attack of Cow-pox, yet I have a single instance before me where the virus acted locally only, but it is not in the least probable that the same person would resist the action both of Cow-pox virus and the

variolous.

LAMARCK

JEAN BAPTISTE PIERRE ANTOINE DE MONET, CHEVALIER DE LaMARCK, was born at Bazentin, France, August 1, 1744. He was educated at the college of the Jesuits at Amiens. After serving in the Seven Years' War he occupied himself in the study of medicine and science at Paris.

His Philosophie Zoologique, in which he outlined his theory of evolution because of the use or disuse of some member of an animal occasioned by its environment, was published in 1809. We give below selections from this work with an introduction to them taken from Problems in Biology. Lamarck died in 1829.

EVOLUTION BY "USE"

There are reasons why Lamarck's system should be of special interest to the student of biology. For it contains the first theory of adaptation through the transformation of species, which is founded upon bare hypothesis, and it may in this respect be regarded as the pattern for all modern biology. It also gives its name to that school which some

what vaguely opposes itself to the explanation of everything organic as the product of natural selection and fortuitous variation. And thirdly, the hypothetical processes and substances of this system have now become, in the ordinary course of research, obvious fiction; so that the doctrine reveals at once its true relation to observation, even without the demonstration of the impossibility and self-contradiction of its typical hypotheses. For Lamarck continually boasts of the sure method of observation, and fills his pages with innumerable references to organic phenomena; but the advance of research has shown that he, like the other biologists of hypotheses, was deceiving himself on this score. For, whatever had been the actual qualities of organisms, they would have supported his theory equally well, so long as they were qualities of organisms.

But even apart from the light which the study of Lamarck throws upon biological problems and methods in general, the system itself is of great interest. It is certain that this biologist has been, on the whole, misinterpreted, but, on the other hand, it is not easy to be sure that one understands him. And the confusion has taken place chiefly over that key-word of his system, besoin, or need. This word has frequently been rendered "desire," and Lamarck has often more than a trace of this meaning in his use of it. But, on reading the whole development of his argument, one immediately finds that neither interpretation may be used exclusively, and that, in fact, besoin is a conception which, for the purposes of the theory, must remain undeveloped and undefined. Use the conception of need alone, and the theory is inadequate ; restrict yourself to the conception of desire, and the whole theory becomes ridiculous, as flippant controversialists have not been slow to find. It is certainly more than need, and as certainly, it is less than desire. It probably appeared to Lamarck to have quite a definite meaning, requiring no further analysis. One can only suppose that he was unconscious of his easy bridge from the ideal relation of necessity to the psychological fact of desirefrom the logical form to the phenomenal process.

In the need, or besoin, we have not, of course, to do with a mere negation. It is not a mere being without or not having. The organism has some kind of reference to the thing which is needed. And since every part of an organism is needed by the rest and by circumstances, it is not difficult to find, in this need, a general principle for the origin of all organic characteristics. All characteristics are alike in this point, though in no other; for simply as parts or organisms, they have relations of ne

cessity with one another. But a mechanism, by which this form of necessity may create the particulars, is wanting to observation. Yet such a mechanism becomes desirable, in order that the emptiness of the theory may be, if only apparently, filled up. The logical distinction must therefore, as we are well accustomed to find, become a quasi-phenomenal difference; and thus there arises the Lamarckian Desire, which is more like Hartmann's Unconscious than it is like anything else, being quite as metaphysical in its origin as is the latter. I shall not attempt the difficult historical question as to what Lamarck supposed his conception of need to include. For our present purpose I merely take his work as it stands, and study it in relation to the problem of adaptation, and watch its development of the old quasi-psychical principle. And I here set down certain important passages from the "Philosophie Zoologique," chapter vii.

"It is evident that the observed form of animals is the product, on the one hand, of the ever-increasing complexity of organization, which tends to form a regular gradation; and on the other hand, of the influences of a multitude of very various circumstances, which tend continually to destroy the regularity of that gradation of the increasing complexity of organization. But I must explain my meaning in these expressions. Circumstances affect the form and organization of animals' means that the former, in becoming very different, change, in course of time, even the form and organization by proportionate modifications. Certainly it would be a mistake to use these words literally, for, whatever be the circumstances, they have no directly modifying effect whatever on form and organization. But great changes in circumstances give rise to great changes in the needs of animals, and such changes in their needs necessarily give rise to changes in their actions. And if the new needs become constant or very lasting, the animals take on new habits which are as lasting as the needs which gave rise to them. It is easy to demonstrate this; indeed, it is obvious without explanation. So that it is evident that a great change in circumstances, when it has become constant for a race of animals, leads those animals into new habits. And, if the new circumstances which have become permanent for a race of animals have given rise to new habits in them (that is, have impelled them to new actions which have become habitual), the result will be the use of such a part in preference to that of such another, and in certain cases the total disuse of such a part as has become useless. Now, none of this is hypothesis or my own opinion; it is, on the contrary, truth which only needs attention and observation of facts to become evident." (P. 222.)

Such, then, is the process of adaptation, to some extent in the individual, and altogether in the race. And the process is the same in each case. Moreover, the same process might be thought to underlie the adaptation of part to part within the development of the individual. A race of animals comes into certain circumstances, or is in them (for the change is not essential to the argument), and suffers no direct change from these circumstances. The latter, however, affect the needs, and the needs condition the actions, which, as habits, affect the form and organization. Just so in the theory of natural selection, the circumstances do not directly affect the race, but all adaptation is referred to the indirect affection of form by the environment. This indirectness of the relation of the individual to circumstance is the form which is first attained by all theories of adaptation, and the special manner of it is a secondary point.

The meaning of this indirectness is that no particular of the organism is changed, except through the unity of the organism, and that changes in organisms have the appearance of being purposeful responses to, rather than mere results of, the changes in the circumstances. And the theories which we are studying have no other object than to derive the present purposeful reaction from a series of direct causes which operated long ago. But it must be noticed that this element of theory, which is as strongly held by Weismann as by Lamarck, completely does away with all those analogies for organic adaptation which are drawn from inorganic things. You may see the coat of rust round a ball of iron, or the shore round a bay, given as parallels to the adaptation of one part of the organism to another or of the whole to its environment. In such cases the relation is perfectly direct, and the change in one element involves a calculable complementary change in the other. But it would appear as though such a direct action of circumstances on organic form takes place, if at all, only within the narrowest limits, either in the individual or in the race. We have seen that the nutritive conditions of form are not answered in the individual by results such as one would expect from the conditions, or such as one could give in parallel degrees with the conditions. The determination of sex, for instance, is hardly the direct result of food supply, in the same sense as the shape of the bay is the direct result of the shape of its shore; and the difference does not seem to be merely that of the extent of our knowledge. Let a race of birds take to the water, and, provided that such changes do in truth occur, its toes become webbed and it secretes oil for its feathers. But