[49] Speaking of the bunt in wheat: "It appears certainly to be contagious, from numerous experiments, which shew that the contagious principle lasts a long time. I have tried it myself; some, however, doubt it, but it cannot be denied, that seed sown, infected with bunt, produces plants similarly affected; every one who has had the slightest experience must be convinced of it."—Essay on the Diseases of Plants. Count Ré.
[50] We have already spoken of the effects of these poisons, and have stated that the amount of each poison capable of destroying the body is pretty accurately known.
[51] The italics are my own.
[52] Gmelin says: "But the mode of action in these transformations, sometimes admits of other explanations; and when this is not the case, our conception of it is by no means sufficiently clear to justify the positive assumption of this, so called contact-action or catalytic force, which, after all, merely states the fact without explaining it"—Gmelin's Hand-book of Chemistry, vol. i. p. 115.
[53] The history and symptoms of some epidemic diseases, such as cholera and influenza, are not inconsistent with the hypothesis that they are caused by the sudden development of animalcules from ova in the blood. But there is a total want of direct observation in support of this hypothesis.—Dr. Williams' Principles of Medicine.
[54] Since writing the above, I have referred for information on this subject, and find, that the Anguillula aceti exhibits sexual distinctions; and that the ovaries of the females are situated on each side of the alimentary canal.—Cyclo. Anat. and Phys. Art. Entozoa.
[55] Speaking of the examination of the infusory animalcules—Mr. Kirby says: "But to us the wondrous spectacle is seen, and known only in part; for those that still escape all our methods of assisting sight, and remain members of the invisible world, may probably far exceed those that we know."—Bridgewater Treatise, vol. i. p. 158.
[56] Mr. Owen has added another class, as the first, called Protelmintha, which comprises the cercariadæ and vibrionidæ.
[57] "It is probable that in the waters of our globe an infinity of animal and vegetable molecules are suspended, that are too minute to form the food of even the lowest and minute animals of the visible creation: and therefore an infinite host of invisibles was necessary to remove them as nuisances."—Bridgewater Treatise, vol. i. p. 159.
"When Creative Wisdom covered the earth with plants, and peopled it with animals, He laid the foundations of the vegetable and animal kingdoms with such as were most easily convertible into nutriment for the tribes immediately above them. The first plants, and the first animals, are scarcely more than animated molecules,* and appear analogues of each other; and those above them in each kingdom represent jointed fibrils."†—Bridgewater Treatise, vol. i. p. 162.