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Part Il—Physical Science.
On tlu: Reproductive Functional Relations of several Species and Varieties of Verbasca.
By John Scott, Esq.,
Curator of the Royal Botanical Gardens, Calcutta.
In this paper, I purpose giving an account of a numerous and carefully performed series of experiments on the hybrid and cross-unions of several species and varieties of Verbasca, with the view of illustrating those functional relations, or differences existing between the results of unions of distinct species on the one hand, with those of different varieties of the same species on the other. I believe, the generally accepted view of naturalists on this point is, that a certain degree of sterility always results from the union of distinct species in their first hybrid produce, and that their progeny are absolutely infertile one with another; while in the cross-unions of varieties of a species, the fertility is in no respect affected in the first cross, and the progeny are, in every case, perfectly fertile, one with another. These relative differences, then, in the products of hybridism and mongrelisui are strongly maintained to be decisively demarcative of the factors, included under the terras "species" and "varieties," affording, so to speak, an unequivocal analysis, whereby nature's original and iiamu