but which only the most learned and the most reflecting will be apt to comprehend. In candor it must be said, that his long career has left some room for the complaint that he did not feel bound to exert fully and continuously all his matchless gifts in behalf of the science of which he was the most authoritative expositor.

But if thus in some sense unjust to himself and to his high calling, Brown could never be charged with the slightest injustice to any fellow-laborer. He was scrupulously careful, even solicitous, of the rights and claims of others; and in tracing the history of any discovery in which he had himself borne a part, he was sure to award to each one concerned his full due. If not always communicative, he was kind and considerate to all. To adopt the words of one of his intimate associates, "those who knew him as a man will bear unanimous testimony to the unvarying simplicity, truthfulness, and benevolence of his character," as well as to "the singular uprightness of his judgment." The remaining, and the most illustrious name of all,—and one in its wide renown strongly in contrast with the last,—has only just now been inscribed upon our obituary list.

The telegraph of the last week brought to us the painful intelligence that the patriarch of science, the universal HUMBOLDT, died at Berlin on the 6th of May. Born in 1769, a year more prolific in great men than any equal period of all preceding time,* Humboldt had, before the end of the eighteenth century, exhibited qualities of the very highest order, and obtained a place of acknowledged celebrity in Europe. This, however, was the mere prelude to his career, for with the close of that century he commenced, with Bonpland, his wonderful exploration of Spanish America, which continued during five years. This journey must be considered in all future time as, substantially, the scientific discovery of Spanish America; and whether we measure its results by the amount of knowledge through the wide fields of Astronomy, Geography, Geology, Mineralogy, Meteorology, Zoology, Botany, and Political Economy, or the personal qualities by which this knowledge was collected and reduced to its place in the records of science, we cannot hesitate to rank the expedition amongst the most important and successful ever executed by man.

On his return to Europe, in 1805, Humboldt was employed several years in reducing his immense collection of materials to form for publication. From that time to his death, a period of almost half a century, he resided (except for a short time, in

* Napoleon, Wellington, Mehemet Ali, Soult, Lannes, Ney, Castlereagh, Chateaubriand, Cuvier, and Humboldt. [The name of Metternich is sometimes added to this list, probably incorrectly. That of Canning certainly does not belong here, nor that of Mackintosh, nor of Sir Walter Scott.-EDS.]

which he made his journey to Northern Asia) in Europe, mostly in France and Germany. The last twelve or fifteen years of this great man were principally employed in the production of his Cosmos,-the crowning labor of his long life, the harvest of his mature wisdom,-a work that could not have been produced by any other man, simply because no other man possessed the treasures, or a key to the treasures, of the various knowledge contained in it.

From his return to Europe to his death, he possessed, indisputably, the first place amongst philosophers, for the vast extent of his acquirements. Without doubt, at all times during the present century there have been men much greater than Humboldt in each special department of science, but no one to compare with him in the number of subjects in which he had but few superiors,-no one who could, like him, bring all the sciences into one field of view, and compare them as one whole, through their relations and dependences. It was probably this extent of knowledge that led him to generalization rather than particular discovery; to trace connections and relations, rather than to search for new and minute facts or particular laws; to produce the Cosmos, rather than discover the atomic theory or the cellular formation of organic structures. Many other men have been masters of several specialties. Humboldt alone brought the whole range of the physical and natural sciences into one specialty.

We cannot close this brief notice of the character and career of our illustrious associate without one moment's allusion to his amiable moral nature, his love of justice, and his superiority to all merely personal ends. So strong was his desire to give the influence of his high scientific position to the cause of civiliza tion and the progress of knowledge, by assisting all applicants for his opinion and advice upon scientific subjects, that he permitted a correspondence to be extorted from him which in his last days became a load too great to be borne, and compelled a cry for relief that had hardly subsided when the news of his death reached us.

Such is the faint outline of a man whose name is indelibly written with those who have been most eminent in this wonderful age of scientific activity. The Academy claims the privilege, in common with the learned societies with which he was associated throughout the civilized world, to express its sorrow for his death, and to offer its tribute of honor to his memory.

ART. XVIII.-On the power possessed by the Larves of various common Flies of consuming, without apparent injury to themselves, the flesh of animals which have died from the effects of Arsenic; by FRANK H. STORER.

Read before the Boston Society of Natural History, January 5, 1859.

SOME months since my attention was attracted by finding several living maggots upon the liver of a subject in the stomach of which I had previously detected the presence of arsenic. This, eight days after death. As this liver was found, on analysis, to be saturated with arsenic, a number of experiments were made for the purpose of ascertaining whether the larvæ observed had really been nourished by the poisoned flesh on which they were discovered.

Several living rats having been obtained, they were fed with cake which contained arsenious acid in various quantities. After eating this they in every case soon died. Their skins having been removed, the carcasses were exposed in a chamber to which flies had free access. In the course of forty-eight hours the bodies of the rats were thoroughly fly-blown, and were soon covered by a multitude of larvæ. Having completely consumed the flesh of the rats-leaving the bones bare, as in the specimen now exhibited to the Society-the maggots concealed themselves in sheltered corners and were converted into chrysalids in due course. These results were constant, having been exactly similar in every instance. Some two dozen or less of these chrysalids being subjected to analysis, metallic arsenic was readily obtained from them. It might be thought that this proves nothing more than that the flesh of the rats contained arsenic, and that, that obtained from the chrysalids had possibly been mechanically attached to the exterior surfaces of the larvæ and not have been swallowed by them. This view would indeed seem to be supported by the fact that as may be seen in the specimen presented-the surface of the bones from which the flesh has been thus devoured is covered with a white powder which has the appearance of arsenious acid. However this may be, only two alternatives remain if it is not admitted that the arsenic found in the chrysalids had really been assimilated by the larvæ : either the latter must possess an instinct which leads them to reject altogether the poison, or it is excreted by them after injestion. In the lack of any positive knowledge of the condition in which arsenic or other inorganic poison exists when contained in organic tissues, it seems idle to dwell at greater length on this point.

It would have been interesting to have preserved the chrysalids in order to ascertain whether they were capable of metamorphosis, and if so, whether the perfect insect would have been healthy and vigorous. I therefore kept a number of them during two months, at the end of which time they were accidentally lost. None of these underwent any change, while a number of diminutive flies, apparently not ichneumons, which obtained access to them, died almost immediately, as was supposed from having fed upon them. The chrysalids were however in a perfect state of preservation, being full of pulp, just before they were lost. The empty shells of other chrysalids, which had been formed at the same time as the above, were nevertheless found about the room from time to time within the six weeks following their formation, indicating that some of them had been metamorphosed, as the appearances of these shells were normal and no larvæ other than those which had fed upon the arsenicated specimens had been admitted to the apartment.

Numerous experiments were now made for the purpose of ascertaining how large a quantity of arsenious acid might be contained in flesh without rendering it unfit food for these larvæ; without much success it must be confessed owing to the facility with which animal tissue is hardened by arsenious acid. If bits of flesh are soaked in an aqueous solution of this substance-no matter how dilute the solution may be-the arsenious acid will unite with the exterior portions of the flesh, forming a compound which, when exposed to the air, dries up in a few hours to the hardness of leather and forms an impervious coating. This hardening may indeed be somewhat delayed by wrapping the flesh in moist cloths, in which case the eggs of flies will often be deposited. These eggs produce living worms, unless so much arsenie has been used that the surface of the flesh is covered with a strong solution of it; but these worms never attained maturity in any of my experiments: they perished for the most part on account of the gradual hardening of the flesh which could not be entirely prevented, or from long continued contact with the solution of arsenious acid, a thin film of which was in some instances allowed to cover the surface of the flesh. In this case the grubs, an hour or two after leaving the egg, would commence crawling about very rapidly, evidently much irritated by the solution with which they were surrounded; this motion would be kept up sometimes during six or eight hours before death ensued.

We all know how quickly flies themselves are destroyed by arsenic-it being the active ingredient of nearly all the popular fly-papers, powders and poisons of the shops-it is a matter of no surprise therefore that the parents of the grubs in question

should have perished by scores, as they did while depositing their eggs upon the poisoned flesh. I may here observe that the only reference to this subject which I have been able to find is the remark of Jaeger (quoted by Orfila, Traitè de Toxicologie, Paris, 1852, I, 379) that "insects, such as spiders, flies, &c., quickly die when arsenious acid in solution is introduced into their digestive organs or applied to their soft exterior parts. The larva of flies live a little longer than the insects which have undergone metamorphosis."

It being impossible to obtain satisfactory results by the method of experimenting which has just been described, I had commenced another series of experiments upon small animals, into the arterial systems of which solutions of arsenic of different degrees of concentration had been injected soon after death. These trials were brought to an abrupt termination by cold weather and the consequent disappearance of all flies. The same difficulties were however experienced here as in the previous cases though in a lesser degree; the flesh having always a tendency to become dry and hard. As this hardening did not take place so rapidly in the injected specimens as where bits of flesh had been soaked in a solution of arsenious acid, so the larvæ were enabled to attain a much larger size, before drying up, than in the previous instances. Indeed in several cases where favorable, moist positions had been secured, they lived for three or four days, becoming quite large and evidently almost ready to pass into the chrysalid state. This, upon the body of a rat weighing seven and a half ounces, into which four and a half grains of arsenious acid in aqueous solution had been injected.

In order to avoid the hardening influence of arsenious acid, solutions of arsenic acid-an eminently hygroscopic substance -were resorted to, but from having been used in too concentrated a state, the larvæ were destroyed, in the course of a few hours after birth, from contact with the solution which had oozed out upon the surface of the flesh; showing clearly, as with arsenious acid, that there is a limit to the amount of arsenic which these larvæ can support.

It is probable indeed that in every case the harmlessness of the poison depends entirely on its being so much diluted that it is no longer present in sufficient dose to destroy the larvæ. I am however inclined to believe that it will be found that they can consume with impunity any flesh into which arsenic has been carried by vital processes. A view which is certainly strongly supported by the fact of finding them upon the arsenicated human liver, an organ which, as is well known, is susceptible of absorbing a particularly large quantity of this poison.