The Unknown.—The problem of the reproduction of the proteus, like that of the common eel, is not yet solved; but ovaria have been discovered in animals of both species, and in this instance, as in all others belonging to the existing order of things, Harvey’s maxim of “omne vivum ab ovo” will apply.
Eub.—You just now said that this animal has been long an object of attention to you; have you studied it as a comparative anatomist, in search of the solution of the problem of its reproduction?
The Unknown.—No; this inquiry has been pursued by much abler investigators: by Schreiber and Configliachi; my researches were made upon its respiration and the changes occasioned in water by its bronchia.
Eub.—I hope they have been satisfactory.
The Unknown.—They proved to me, at least, that not merely the oxygen dissolved in water, but likewise a part of the azote, was absorbed in the respiration of this animal.
Eub.—So that your researches confirm those of the French savants and Alexander von Humboldt, that in the respiration of animals which separate air from water, both principles of the atmosphere are absorbed.
Phil.—I have heard so many and such various opinions on the nature of the function of respiration during my education and since, that I should like to know what is the modern doctrine on this subject. I can hardly refer to better authority than yourself, and I have an additional reason for wishing for some accurate knowledge on this matter, having, as you well know, been the subject of an experiment in relation to it which, but for your kind and active assistance, must have terminated fatally.
The Unknown.—I shall gladly state what I know, which is very little. In physics and in chemistry, the science of dead matter, we possess many facts and a few principles or laws; but whenever the functions of life are considered, though the facts are numerous, yet there is, as yet, scarcely any approach to general laws, and we must usually end where we begin by confessing our entire ignorance.
Eub.—I will not allow this ignorance to be entire. Something, undoubtedly, has been gained by the knowledge of the circulation of the blood and its aëration in the lungs—these, if not laws, are at least fundamental principles.
The Unknown.—I speak only of the functions in their connection with life. We are still ignorant of the source of animal heat, though half a century ago the chemists thought they had proved it was owing to a sort of combustion of the carbon of the blood.