of one of the sauri, the remains of which
are found in the older secondary strata. It was said at this time that
no organs of reproduction had been discovered in any of the specimens
examined by physiologists, and this lent a weight to my opinion of the
possibility of their being actually new creations, which I suppose you
will condemn as wholly visionary and unphilosophical.

_Eub_.--From the tone in which you make your statements, I think you
yourself consider them as unworthy of discussion. On such ground eels
might be considered new creations, for their mature ovaria have not yet
been discovered, and they come from the sea into rivers under
circumstances when it is difficult to trace their course.

_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 ch