This paper the author considered as nothing else than an abstract of the thoughts he entertained on the subject. His object was to shew there was no analogy in nature, rendering a prospective law of progressive development from lower to higher types probable; and he brought forward various examples to prove that, in all cases in which variation took place among domestic animals and vegetable productions, the varieties, though they might be regarded as improved or new, were not permanent, but required selection and care to preserve them; so that new forms and qualities appearing, could not confirm the progressive hypothesis.