lectures should be illustrated by experiments, he adopted this plan, and likewise abandoned the old practice of reading lectures. He used to express himself very strongly on the inutility of merely reading lectures. Although he first adopted Dr. Marcet's experiments in his classroom, he soon so far improved upon these, that his own became a model for the chemical class-rooms of Europe.

During the early period of his residence at Stockholm, he practised the profession of medicine, and in 1807 was mainly instrumental in forming the Medical Society of that capital. In 1810 he was made President of the Royal Academy of Sciences at Stockholm; and in the same year received the appointment of Assessor of the Medical College; and was made a member of the Royal Sanitary Board. At this time, though scarcely more than thirty years of age, he had obtained great reputation as a chemist. He had published a work on animal chemistry, containing many original investigations on the fluids of the animal body, and which was subsequently translated-as, indeed, have been most of his works-into almost every language of Europe. In conjunction with Hisinger, he commenced, in 1806, the publication of a periodical work entitled, "Afhandlingar i Fysik, Kemi, och Mineralogi," which contained a series of papers by himself, constituting some of the most valuable contributions that had yet been made to analytical chemistry. His labors were regarded of so much importance by the Royal Academy of Stockholm, that that body decreed him, in 1811, 200 dollars yearly for his chemical researches. In 1812, Berzelius visited England, where he was most cordially received. In that year he communicated, through Dr. Marcet, a valuable paper to the MedicoChirurgical Society of London, "On the Composition of the Animal Fluids." In 1818 he visited France and Germany-countries in which he was better known than in Great Britain, as most of his papers and works were published in the languages of those countries, as well as in that of Sweden. In the same year he was appointed Secretary to the Academy of Sciences-a post which he held till his death. In 1831 he was allowed to retire from the active duties of his professorship at the Caroline Institute, but he still held the title of honorary professor. Up to this time he had resided in apartments provided for him at the building occupied by the Academy of Sciences,-where, on the same floor, he had his study and laboratory, so that he could with little difficulty pass from his desk to his crucible, and husband his time to the greatest possible extent. He now, however, moved to a house of his own, and in 1835, married a daughter of the town-councillor (Staatsrathe) Poppius. In 1837 he received the Great Gold Medal of the Royal Academy of Stockholm,-and in 1840 the Diet of Sweden voted him a pension of 2,000 dollars per annum. The scientific societies of Europe and America contended for the honor of enrolling his name among their members,-and with eighty-eight of these bodies it was connected. Nor was his sovereign, Charles John, behindhand in recog. nizing the most distinguished of his adopted countrymen. In 1815 Berzelius was made a Knight, and in 1821 a Knight Commander, of the Order of Vasa. In 1829 he received the Grand Cross, and in 1835 was made a Baron. The intelligence of this honor was conveyed to Berzelius by the hand of the King; who wrote himself a letter intimaSECOND SERIES, Vol. VI, No. 18-Nov., 1848.

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ting his deep sense of the merits of the philosopher, and expressing a hope that in this nomination the world would recognize an homage paid to the man who had consecrated his life to those useful researches which had been already recognized by Europe, and which it was the glory of Sweden to be able to appropriate as the patrimony of one of her children. This letter was sent to Berzelius on his wedding-day. How few men of science have married with a patent of nobility on the breakfast table! Sweden had, however, yet one more ovation for her beloved son. In 1843 he had been a quarter of a century Secretary to the Academy, and on this occasion a festival was given in his honor. The Crown-Prince was in the chair,-and a portrait of the chemist painted by Lieut. Col. Lodemark was presented to the Academy.

In addition to the works already mentioned, he published a “Manual of Chemistry," which went through several editions, that of 1841 consisting of ten volumes,—and, we believe, another larger edition has since been published. In 1822 he commenced the publication of an Annual Report on the Progress of the Physical Sciences, which has been published every year to the present time.

The name of Berzelius has been too intimately connected with the history of chemistry for the last forty years, for us in this slight sketch to give an adequate idea of the influence which his discoveries and generalizations have exerted upon the science. To him it is indebted for the discovery of several new elementary bodies,-more especially selenium, thorium and cerium. He first demonstrated the acid nature of silica, and was thus enabled to throw light on the composition of a series of interesting mineral compounds of silica with the metallic oxyds. This subsequently led to a whole re-arrangement of mineral bodies, and contributed greatly to the advance of mineralogy. His discovery of selenium led him to investigate its various compounds, and compare them with the sulphurets. These investigations again resulted in his generalizations on the nature of the sulphur salts, and a new classification of the various salts. Subsequently, he investigated the compounds of fluorine, and arrived at some of the most important and valuable results that have yet been obtained by the analytical chemist.

Whilst Berzelius was writing the first edition of his "Manual of Chemistry," Dalton had promulgated his idea of the atomic constitution of matter, and Davy had made his great discovery of the metallic bases of the alkalies. These directed his attention to the laws of com. bination. He was led to institute researches with the most scrupulous care into the combining proportions of the various elements, giving to each its correct number, and was enabled to obtain results perfectly harmonious with theoretical calculations made on Dalton's laws. He was enabled to extend Dalton's law that one atom of one body unites with one, two, or three, &c., atoms of another body, and showed that two atoms would unite with three and five. He also pointed out the great fact, that two compounds which contain the same electro-negative body always combine in such proportions, that the electro-negative element of one is a multiple by a whole number of the same element of the other. He not only gave to the elementary bodies their combining numbers, but introduced the system of symbols, by which chemical labor has been so greatly facilitated. Till the time of Berzelius, organic

chemistry was a waste, with here and there an attempt to explain the phenomena of living beings upon chemical principles, and which from the entire want of experimental foundation, was even worse than useless. The compounds found in plants and animals were not supposed to come within the category to which the laws of combination applied. Berzelius was the first to show that these laws could be applied to animal and vegetable products; and in so doing, he opened the way for the discoveries of Mulder, Liebig, Dumas, Boussingault, and others.

As a skilful manipulator, Berzelius has had few equals in the history of chemistry. To this we are indebted for the immense variety, number and success of his analyses. Many of the analytical processes in use at the present time, have had their origin with him.

The personal appearance of Berzelius was that of a strong, healthy man, with nothing in his habits or manners to impress a stranger with a sense of his powers. A chemist who visited him says, "He has nothing of pretense, reserve, or singularity about him; so that his plainness drew from a fellow-traveller of mine, whom he allowed me to introduce to him, the observation, 'I would never have thought him the great man he is said to be.'" His attention to strangers was very great, especially to those who took an interest in chemistry. With these he would frequently spend hours in his laboratory, explaining his methods of working, and on their departure, he left the impression that he was the honored party. He was an early riser, and gave the first part of the day to his most important work, whatever that might be. He seldom either wrote or experimented in the evening, leaving that part of the day for reading and social relaxation. He had no particular times for writing or experimenting; when he had a work to finish, he would write sometimes for months without performing an experiment, but if anything of importance occurred to him during his writing, requiring further investigation, he would at once give up the pen, and work perhaps for weeks in his laboratory. Few men were more beloved in the city of Stockholm than Berzelius.

Were the merits of this great chemist less, we might not be able to afford to hint at any defects. But regarding him at a distance, he appears to us to have carried his caution beyond the requirements of scientific research. His feelings were conservative, and though constantly going forward to the new, he still clung with tenacity to the old. He was almost the last chemist of eminence that admitted Davy's theory of the elementary nature of chlorine. Even after envy and prejudice had given up their opposition, the caution of Berzelius withheld assent. In the recent advances of organic chemistry, also, and more especially in its applications to the physiology of plants and animals, Berzelius has looked on with the eye of a critic, and withheld to the last his adhesion to some of the advanced positions of this department of the science.

A letter from RETZIUS, (L'Institut, No. 764,) speaking of Berzelius, states that on examination, it was found that there was a softening of the posterior half of the spinal marrow corresponding to the tenth dorsal vertebra.

VI. BIBLIOGRAPHY.

1. Rare and Remarkable Animals of Scotland, represented from liv ing Subjects, with practical observations on their nature; by Sir JOHN GRAHAM DALYELL, Bart. Volume first, containing fifty-three colored plates. London: John Van Voorst, Paternoster Row, 1847. 4to, pp. 270, (Ann. Mag. Nat. Hist., ii Ser., i, 311, 1848.)-The most interesting chapter in this interesting volume is that which narrates the history of the Hydra tuba. This marine animal is called a Hydra by our author because it has the form and the characters of the freshwater polyps, and possesses also their qualities-their greed of living prey (p. 87), their proliferous evolution of young, their endurance of priva tions, their power to recover from apparently immedicable wounds, and their strange germinations and monstrosities under the influence and direction of the experimentalist (p. 93). This hydra is found attached to submarine bodies; the body is fleshy, inversely conical, encircled about the oral disc with a series of long slender thread-like tentacles, and thus it lives apparently for an indeterminate period, exercising all the functions of a perfect and adult animal even to the repeated production of young in all respects alike the parent. So it lives until, from some unknown causes, a change comes over it, and it begins to unveil itself, and to exhibit one of the most wonderful revelations in animal transmutations. A pendulous column or roll is observed as if implanted on the disc of the hydra; at first it is faintly indented by circles and is terminated by a circular row of tentacles; the indenting circles become more deeply waved, the tentacles shorter until they are obliterated; and then each roll of the column is successively separated and liberated from the others until the whole embry. onic column is dissolved, the individual rolls floating at freedom in the bosom of the waters, obviously the young of one of those large Medusæ which swarm our seas in the months of the latter summer and autumn! -Now this short sketch of the metamorphosis is not of any new discovery, for Sars had made us in some degree acquainted with it, but the account of it given by Sir John Dalyell excels all others in fullness and completeness, and in its freedom from conjectural explications. The metamorphosis itself is wonderfully curious, but what strikes us as the most unaccountable fact in the process is the uncertainty of the periods at which the change takes place. The Hydra tuba may remain for years a hydra propagating its kind, and we know of no data to fix the period when it shall begin the process of change into its mature and final state; and, to add wonder to wonder, having cast off several of these medusean embryos, a basis remains out of which another Hydra tuba shall arise, to go through the same hydra life and the same medusean metamorphoses as its prede cessor. We suppose that these facts-for facts they are-will not sup port the opinions of Steenstrup on alternating generations, nor can even be reconciled with them.

The way in which Sir John discovered that the Hydra tuba was the embryo of a Medusa was this: he took a large Medusa, of undetermined species but beautifully figured on plate 15, and placing it in a

vase of sea-water the spawn-"a brownish matter like dust"-was shed from its ovarian fringes and settled at the bottom. This spawn consisted of "an host of animated creatures in quick and varied motion," partaking much of the nature of the planules of the Sertularians. The changes they rapidly underwent were noted and delineated; and in eleven or twelve days after "the planule had been discharged from the unwieldy Medusa, it was converted to a stationary hydra," (p. 105.) "This new animal was provided with a complement of eight arms, yet so immature as to be of unequal dimensions. Different groups, under metamorphosis, showed the utmost irregularity in respect to evolution, in their shape and proportions: nor was it until thirteen days later, or three weeks after their birth, that any appeared with eight regular tentacles. Thus was a most perplexing problem solved-the Hydra tuba proved to have sprung of a Medusa." (p. 105.)

The progress of discovery went on. Sir John had "remarked colonies of minute transparent animals swimming in vessels of sea-water, during the months of February, March and April. Their general aspect very much resembled a flock of birds in distant flight, as represented by landscape painters. After being transferred to vessels free of other subjects, they continued several days in activity and then disappeared. I could not account either for their origin or their transience. They occurred only at rare intervals, and always identically under the same form." (p. 111.) These very minute beings, for the expansion of an individual is only between one and two lines, were evidently allied to the Medusa "both in configuration and in habits," but they differed from the Medusa in the early date of their appearance. To distinguish them Sir John called the species Medusa bifida, and we have it minutely described and variously figured. Sir John was first led to remark that it was chiefly observed in vessels containing the Hydra tuba (p. 114); and subsequently, and as it were by accident, he discovered that the hydra was in fact their source; and moreover that the hydra was identical with the Strobila of Sars! The discovery is told in a most interesting manner, and with a truthfulness which there is no gainsaying.

We shall quote only a few of the many passages we have marked, previously observing that the Hydra tuba in its strobila form is something like a fir-cone or a cylinder cut into several whorls, each whorl, when detached, becoming what is named the Medusa bifida. The strobila throws off these whorls in succession to the number of from ten to twenty, when the basis, as already stated, resumes the form and habits of the hydra.

"First, a smooth fleshy bulb sustained a cylinder of about half its own diameter, indented by plain circles, which were soon converted to waving curvatures. A row of twenty or twenty-four tentacula crowned the summit of the cylinder, which row disappeared or was obliterated as the waving in its vicinity deepened, and the diameter of the cylinder there expanded, that is towards the summit. Concomitant on obliteration of the terminal row, a new circle of tentacula, at first few, but gradually augmenting, was emerging from around the bulb, while the struggles of Medusa, into which the waving strata were evolving, accomplished their liberation to swim unconstrained in the surrounding element." (p. 121.)