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regards their mode of reproduction as belonging to the gemmiparous type. Viewed in this way, the different broods cannot be looked upon as so many generations; but on the contrary, the whole suite, from the first to the last, that is, till the production of a winged Aphis, constitute but a single generation. This explanation by a species of budding seems far more satisfactory than that which supposes that either cells or nuclei of the first individual are transmitted by successive inclusions to the last. As this latter idea cannot be supposed to be the result of direct observation, and as no proof is adduced that identical cells and nuclei really pass from one generation to the other, the whole stands merely as an ingenious theory, while Dr. Burnett's explanation [and this view is not proposed for the first time by him,] is in accordance with direct observation. But, in accepting his view, we are compelled to admit the hypothesis, that the germinating force imparted to the first ova is transmitted to the successive broods without the aid of spermatozoa.

"On the microscopic appearances presented in the intestinal discharges and muscular fibres of a patient who died of the epidemic cholera."

"Tissue and its retrograde metamorphosis."

"On the Geology and other points connected with the natural history of Florida."

"Considerations on a change of climate by northern invalids, and on the climate of Aikin, S. C."

"Considerations of some of the relations of climate to tubercular disease."

To these should be added his various critical notices of recent scientific publications in Silliman's Journal, which in view of the short time he occupied the position of associate editor, were quite voluminous, and serve to give us a good idea of his powers of analysis and discussion.

There is no one of his productions, which embodies more of the results of his labors, than the prize dissertation, consisting of two hundred closely printed octavo pages, presented to the American Medical Association in the year 1851, and entitled "The Cell, its physiology, pathology and philosophy, as deduced from original observations; to which is added its history and criticism. ' Natura in minimis maxima est.'"

To those who are acquainted with modern physiology, it will be seen at once that he had selected a great subject, one which even the most accomplished minds might approach with distrust. The nucleated cell! that minute organic structure which the unaided eye cannot discern, yet constituting the first stage of every living being, the seat of so many of the complex phenomena of animal and organic life, and the agent by which even the mind itself retains its grasp and exerts its influence upon the living

structures with which it is associated. In entering upon so difficult a subject as this, it was not expected, nor is there any reason to suppose that he himself expected, that he should not lay himself open to criticism. The ablest living histologist, Kölliker, in speaking of the subject of the development of tissue, uses the following language: "Not only does histology not possess a single law, but the materials at hand from which such could be deduced are as yet relatively so scanty, that not even any considerable number of general propositions appear well founded." As laws and general propositions were among the especial objects of Dr. Burnett's researches, it will be seen at once that he has entered boldly into a contested field. But it is to follow him in his labors, and not to hold up to criticism his results, that we have at present to do.

His subject is discussed under the following heads:

1st. Cell-genesis, under which he treats of the origin of cells, and advocates a peculiar mode of development, which he claims as original with himself, and the result of his own observations. 2d. Cell physiology, or healthy function.

3d. Cell pathology, or diseased function.

4th. Cell philosophy, or 1st, the relations of cells to the teleological view of organization; 2d, the direct agency of cells in the production and manifestation of nervous power, the intellectual processes, &c.

The general results of his studies of cell life and cell genesis are in his own words as follows: "The great outstanding fact which appears before us as the result of these studies is, that there is fundamental unity of organization. This we have seen to consist in elementary particles, which in both animals and plants are formed upon a common plan. It was the opinion of Schwann and Schleiden, who truly originated this view, that this plan consisted in the preexistence of a solid fundamental body, (the nucleus) around which is formed a membrane ultimately expanding and constituting the cell. It has been one of my objects to show, that this is not of universal application, by an attempt to demonstrate another mode of cell formation, which is that the fundamental idea of a cell is a simple vesicle, and that the nucleated cell is simply one cell containing another within its walls. With Schwann the nucleus is exogenous and germinative-with me the nucleus is endogenous and reproductive.

"The two conclusions of the studies of cell life are then 1st. The existence of an elementary particle, having an invariable unity of expression, the cell. 2d. The universality of the application of this particle for the formation of organized parts, the tissues."

In studying cells in relation to pathology, he regards this last as an erring physiology, and concludes, that, both as to their gen

esis and general aspect as cells, those which belong to abnormal cannot be distinguished from those belonging to normal conditions of life. The genetic and general relations of cells in physiology and pathology are therefore the same. Their difference does not relate to structure, but to their destiny. Physiological cells must be considered teleologically, but pathological ones have no ulterior object.

Each of the different heads of his dissertation he discusses with great ability, and gives ample evidence that he is not only familiar with the scientific labors of others, but that he is perfectly at home in the different departments of investigation which his essay involves. If it be allowable to express an opinion of its merits in general terms, it may be truly said that it gives evidence of wonderful zeal and industry in research, of acute powers of observation, and of great readiness in perceiving general relationships. It is in connection with this latter faculty that he seems the most liable to error. He appears to have partaken something of the spirit of Oken, and to have given way at times to the suggestions of the imagination, instead of subjecting himself to the severe mandates of reason, and the rigid rules of induction. This is naturally the fault of youth, and for which scientific minds, at the present time, with their tendencies to hasty generalization, may be justly said to be in part responsible. But in one who combined industry, a desire for truth, and an almost unlimited patience in observation, it might have been fairly anticipated that, sooner or later, the better and safer qualities of the mind would have eclipsed all others.

While constantly active as an observer, Dr. Burnett found time. to engage in another service which occupied some of the latest hours of his life, and the non-completion of which was a source of anxiety to him in his last moments. This was the translation from the German, of the Comparative Anatomy of Siebold and Stannius. All who are familiar with the published volume, will not fail to see in it another proof of his industrious habits as exhibited not in the translation merely, (itself in this case no ordinary labor) but in the numerous additions to science which, scattered far and wide through scientific journals, have been brought together, and in the contributions he himself has made from his own stores of accumulated observations.

The last scientific investigation to which his time was devoted was into the natural history of the Orange insect, which is so destructive to the orange trees of Florida. The habits of this insect he had studied during his last winter's residence in Florida, and had prepared a memoir in reference to it for the American Association for the Advancement of Science, but his ill health prevented his attending their recent meeting.

Such is an imperfect sketch of the scientific labors of our late associate. It only remains to consider his life from another point of view, in regard to its moral aspect. Of this I do not feel justified in treating at length, as my relations to him were not sufficiently intimate to speak from personal observation; but from all I can learn from his associates, from his fellow-students and his more intimate friends, he was a kind and affectionate son and brother, one who enjoyed to an unusual degree home and all its associations; he was a man of a truly benevolent heart, into which irreverent thoughts seemed to gain no admission, or from which they certainly obtained no expression. In all of his studies of nature he seems to have had a pervading perception of God in his works, and often in eloquent words gives expression to his feelings, when some new manifestation of divine wisdom was uncovered to his inquiring mind.

Dr. Burnett's zeal and devotion could not fail to awaken a warm interest wherever he went, among those with whom he associated. He became acquainted with the leading naturalists of the country, and obtained from them and others, willing aid and counsel, as well as respect for his great acquirements. To them he always felt warm feelings of gratitude. But there was one, to whom, more than all others, he was especially grateful, a friend and relative, who at an early period, perceived the indications of uncommon promise for the future, and who with kind heart and benevolent purpose aided and encouraged him in all his undertakings.

He had religious faith and religious hope. To a speculative mind like his, it seemed almost a matter of necessity that the momentous questions which the problem of life involved, should sooner or later, have been presented for examination and discussion, and that before any settled convictions could be reached, they should have found him perplexed and in doubt. Doubts and perplexities in his mind did exist, but eventually they gave way and were replaced by faith and hope, which lightened his burden when, weary and exhausted, he approached the end of life. He had been long accustomed to look upon death and to talk about it as an event that he must meet at an early period. But death, if not imminent, is something that all look forward to calmly and without emotion, and when we speak of it we are not sure that we give utterance to our most solemn feelings and convictions. But there is one moment when, if ever on earth, the heart, if it opens itself, does so without disguise, if it give utterance, does so without reserve; it is that dread moment when death approaches so near that there is no alternative but to look upon earthly life as finished, its account made up, and when all that remains for the mind to dwell upon, is the dissolution of the body and the realization of another life. A few days before he

died our late associate returned after a winter's absence, to the home of his family, his bodily health exhausted, his energies prostrate. At first he entertained the hope that as before, rest and quiet might restore him partially at least to his usual health, and that he might have yet another opportunity of continuing those labors which he so fondly cherished; but his fast declining strength, the anxiety of those around him, the announcement of his physician and his own quick perceptions soon told that life was drawing to a close, and that for him the great moment was near. In all this he was calm and serene, conversed on the approaching separation without faltering, gave utterance to expressions of deep affection to those who were bound to him by the ties of kin, uttered his prayer for forgiveness, and expressed the solemn conviction, which now rose paramount to every other, that if there yet remained much for him to live for, there was yet far more to die for. On Saturday morning, July 1st, a few days. before the completion of his twenty-sixth year, he died.

We cannot but sensibly feel, that in his death we have lost an associate of no ordinaty talents; we can point to no other member of our Society, and to not more than one other naturalist in our country, who has given such proofs of zeal and industry, and who, in so short a life, has accomplished so large an amount of scientific labor. Had he been spared to future years, we cannot but feel the assurance that he would have acquired for himself a far higher place and a still more honorable name in the annals of science. Let us cherish his memory and profit by his example.

The Resolutions which follow, prepared at the request of the Society by Prof. Wyman, were unanimously adopted:

Resolved, That the members of the Boston Society of Natural History have learned with deep regret the death of Dr. Waldo Irving Burnett; that, in his decease, we have lost a most active. and zealous associate, and science an ardent, disinterested and productive laborer.

Resolved, That to the family of our late associate, we would offer our deep sympathy for their affliction, in the loss which they have sustained by the early death of one, with whose memory is associated so much of honorable devotion and noble selfsacrifice.

On motion of Dr. Abbott, it was voted, that Dr. Wyman be requested to prepare a copy of the Notice and Resolutions for publication in Silliman's Journal.

[It is with deep sorrow that in place of the usual Contribution from Dr. Burnett for this Journal, we have to present to our readers his obituary. One of the most earnest, faithful and profound laborers in science in the country has ceased from his work while