lake of Guarda, the Benacus of the ancients, the magnificent trout, or _Salmo fario_, which in colour and appearance is like a fresh run salmon, spawns in the river at Riva, beginning to run up for that purpose in June, and continuing to do so all the summer; and this river is fed by streams from snow and glaciers in the Tyrol, and is generally foul: whilst the small spotted common trouts, which are likewise found in this lake, go into the small brooks, which have their sources not far off, and in which, it is probable, they were originally bred. I have seen taken in the same net small fish of both these varieties which were as marked as possible in their characters:—one silvery, like a young salmon, blue on the back, and with small black spots only; the other, with yellow belly and red spots, and an olive-coloured back. I have made similar observations in other lakes, particularly in that of the Tarun near Gmunden, and likewise at Loch Neah in Ireland. Indeed, considering the sea trout as the type of the species _trout_, I think all the other true trouts may not improperly be considered as varieties, where the differences of food and of habits have occasioned, in a long course of ages, differences of shape and colours, transmitted to offspring in the same manner as in the variety of dogs, which may all be referred to one primitive type.[4] PHYS.—I am somewhat amused at your idea of the change produced in the species of trout by the formation of particular characters by particular accidents, and their hereditary transmission. It reminds me of the ingenious but somewhat unsound views of Darwin on the same subject. HAL.—I will not allow you to assimilate my views to those of an author, who, however ingenious, is far too speculative; whose poetry has always appeared to me weak philosophy, and his philosophy indifferent poetry: and to whom I have been often accustomed to apply Blumenbach’s saying, that there were many things new and many things true in his doctrines; but that what was new was not true, and what was true was not new. POIET.—I think Halieus is quite in the right to be a little angry at your observation, Physicus, in making him a disciple of a writer, who, as well as I can recollect, has deduced the _genesis_ of the human being, by a succession of changes dependant upon irritabilities, sensibilities, and appetencies, from the _fish_; blending the wild fancies of Buffon with the profound ideas of Hartly, and thus endeavouring to give currency to an absurd romance, by mixing with it some philosophical truths. I hope your parallel will induce him to do us the favour to state his own notions more at large.