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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;’1 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 