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8 a few hours before. . . . . I have seen specimens, again, of another species growing on a leaden cistern at Kew, from which it could derive no nutriment. Another was found by Sowerby on cinders on the outside of the dome of St. Paul's."

Until lately, no question has been raised as to the organisms belonging to this group having been rightly placed amongst the Fungi; but in the "Botanische Zeitung" for 1858 (t. xvi, p. 357), Dr. De Bary expressed an opinion that they are animals, and he has since maintained this view in an elaborate essay in Siebold and Kölliker's "Zeitschrift für wissens-chaftliche Zoologie." His argument is founded partly upon the peculiarities of growth above referred to, but more particularly upon the nature of their component substance, which he considers almost identical with sarcode.

He also lays some stress upon the fact, that the Myxogastres, at an early stage of their growth, exhibit in the substance of their bodies solid matter taken in from without, such as cells of algæ, spores of fungi, &c. He says that if these ingesta can be considered to be food, the fact would establish the animal nature of the Myxogastres, because, if an organism eats, it must be an animal. He admits, however, that there is no proof that the ingesta are food, and that the solid bodies in question may have gained admittance accidentally.

Mr. Berkeley, in combating De Bary's views, observes:—"A sufficient answer is the fact, that some of the species contain spiral vessels, and have their spores surrounded by a distinct sac."

The latter objection is strong, and is one which De Bary has not met, having contented himself with simply calling in question some observations on the genera Badhamia and Enerthenema, in which Mr. Berkeley and other observers allege (as we believe correctly) that such a sac exists. With regard, however, to the spiral vessels, we think Mr. Berkeley states their existence too confidently. It is true that all the species of Trichiæ contain threads, sometimes short and fusiform, sometimes of great length, and forming almost a net-work, all of which threads bear spiral markings; but the nature of these markings is still a subject of controversy, and the determination of the question is dependent upon microscopical investigation, and, like the question as to the markings on the valves of the Diatomaceæ, will probably long continue undecided. De Bary, it may be observed, adopts unhesitatingly the opinion expressed in the "Microscopical Journal" (vol. iii., p. 15), according to which the spiral markings of the Trichiæ are not produced by the existence of a spiral fibre, but are an optical effect arising from an arcuate elevation of the cell-wall, following a spiral direction from one end of the threads to the other.

In commenting upon De Bary's observations, M. Tulasne has called attention to a fact in support of his views, viz., the existence in the external covering of the Myxogastres of a white calcareous salt, which effervesces in sulphuric acid. "I am surprised," says M. Tulasne, "that M.