Page:Proceedings of the Royal Society of London Vol 1.djvu/382

Rh that supplied, as usual, the heart, the lungs, and the stomach he- longing to its own side of the body, and then gave branches, as usual, to the semilunar ganglion.

A pair of inbercostsls also proceeded from each head. The left intercostal from one, and the right intercostal from the other, proceeded as usual; but those which passed down between the two spines, and adjacent to each other, neither gave oﬂ' nor received communicating branches, and did not form the usual ganglia, for want of all the cervical, dorsal, and lumbar nerves excepting the ﬁrst cervical. The other nerves were in general distributed as if the body had had but one spine : thus the nerves of the right arm were supplied from the right side of the right spinal marrow, and those of the left arm came from the leﬁ side of the left spinal marrow.

The author next proceeds to such remarks as naturally arise from the contemplation of so singular a production. And the ﬁrst observation is, that although there were here combined, in the same system, duplicates of several parts, yet there appeared, upon inspection, to be no reason why the functions of life might not have been properly performed. An apparent uniformity prevailed throughout, without abruptness, in the transition from the double to the single structure. Two stomachs terminated in one track of intestines, somewhat more capacious than usual. Although the vascular system was furnished with two hearts, the principal vessels were arranged and united together, so that no impediment seemed to exist to the circulation of the blood. For regulating the supply of blood to each heart, a communication was established between the vena cava superior of one heart, and the vena cava inferior of the other.

The nervous system presents also a wide ﬁeld for conjecture. The function of the two brains appeared to be as independent of each other as those of any two individuals of the same family; and the reasoning faculties, it is presumed, might have been very opposite, excepting so far as they would have been inﬂuenced by the same habits, and by the same course of education ; and their sensual inclinations (if any such existed) would probably be very different.

As the vital organs conspired together in carrying on the same process of life, so did the nerves of these involuntary parts unite for the same purpose, though originating from diﬁ'erent heads. But, on the contrary, those nerves which supply the voluntary organs were as completely unconnected with each other as if they had belonged to diﬂ'erent bodies. So that although in all involuntary and indispensable functions there would probablyhave been the most perfect harmony, considerable inconvenience might have arisen, where locomotion was concerned, if the two heads, thus inseparahly coupled, had not had the same inclination.