Much light has been thrown upon many of the most important and intricate functions of the animal machine, by accurate inquiries into the processes of nature under extraordinary circumstances. The doctrine of conception, lately advanced, owes its support, in no small degree, to observations made on cases, in which, from adventitious causes, Nature has been led out of her ordinary tract. The following case appears to be of such a description; and, as tending further to elucidate the subject, may probably be not unacceptable to the learned members of this Society.