raptures about the eggs of the "Hebammen Krote," and will raise them. . .Schweiz takes your place in our erudite evening meetings. I have been lecturing lately on the metamorphosis of plants, and Schimper has propounded an entirely new and very interesting theory, which will, no doubt, find favor with you hereafter, about the significance of the circular and longitudinal fibres in organisms. Schimper is fruitful as ever in poetical and philosophical ideas, and has just now ventured upon a natural history of the mind. We have introduced mathematics also, and he has advanced a new hypothesis about comets and their long tails. . . Our chief botanical occupation this summer is the careful observation of all our plants, even the commonest, and the explanation of whatever is unusual or enigmatical in their structure. We have already cracked several such nuts, but many remain to be opened. All such puzzling specimens are spread on single sheets and set aside. . .But more of this when we are together again. . .Dr. Leuckart begs you to study carefully the "Hebammen Unke;"* (* Bombinator obstetricans referred to in a former letter.) to notice whether the eggs are already fecundated when they are in the earth, or whether they copulate later in the water, or whether the young are hatched on land, and what is their tadpole condition, etc. All this is still unknown. . . AGASSIZ TO BRAUN. ORBE, June 10, 1827. . . .Last week I made a very pleasant excursion. You will remember that I have often spoken to you of Pastor Mellet at Vallorbe, who is much interested in the study of the six-legged insects. He invited me to go to Vallorbe with him for some days, and I passed a week there, spending my time most agreeably. We went daily on a search after insects; the booty was especially rich in beetles and butterflies. . .I examined also M. Mellet's own most excellent collection of beetles and butterflies very carefully. He has many beautiful things, but almost exclusively Swiss or French, with a few from Brazil,--in all about 3,000 species. He gave me several, and promises more in the autumn. . .He knows his beetles thoroughly, and observes their habits, haunts, and changes (as far as he can) admirably well. It is a pity though that while his knowledge of species is so accurate, he knows nothing of distribution, classification, or general relations. I tried to convince him that he ought to collect snails, slugs, and other objects of natural history, in the hope that he might gain thereby a wider insight. But he would not listen to it; he said he had enough to do with his Vermine. My brother writes me that my box has arrived in Neuchatel. As I am going there soon I will take it then. I rejoice in the thought of being in Neuchatel, partly on account of my brother, Arnold (Guyot), and other friends, and partly that I may study the fishes