All such phenomena, Dr. Passavent attributes to the interaction of imponderables—or of one universal imponderable under different manifestations—which acts not only within the organism, but beyond it, independently of all material obstacles; just as a sympathy appears between one organ and another, unobstructed by the intervening ones; and he instances the sympathy which exists between the mother and the fœtus, as an example of this sort of double life, and standing as midway between the sympathy between two organs in the same body and that between two separate bodies, each having its own life, and its life also in and for another, as parts of one whole. The sympathy between a bird and the eggs it sits upon, is of the same kind; many instances having been observed, wherein eggs, taken from one bird and placed under another, have produced a brood feathered like the foster instead of the real parent. Thus, this vital force may extend dynamically the circle of its influence, till, under favorable circumstances, it may act on other organisms, making their organs its own. I need scarcely remind my readers of the extraordinary sympathies manifested by the Siamese twins, Chang and Eng. I never saw them myself; and, for the benefit of others in the same situation, I quote the following particulars from Dr. Passavent: “They were united by a membrane which extended from the breast-bone to the navel; but, in other respects, were not different from their countrymen in general. They were exceedingly alike, only that Eng was rather the more robust of the two. Their pulsations were not always coincident. They were active and agile, and fond of bodily exercises; their intellects were well developed, and their tones of voice and accent were precisely the same. As they never conversed together, they had nearly forgotten their native tongue. If one was addressed, they both answered. They played some games of skill, but never with each other; as that, they said, would have been like the right hand playing with the left. They read the same book at the same time, and sang together in unison. In America they had a fever, which ran precisely a similar course with each. Their hunger, thirst, sleeping, and waking, were alway coincident, and their tastes and inclinations were identical. Their movements were so simultaneous, that it was impossible to distinguish with which the impulse had originated; they appeared to have but one will. The idea of being separated by an operation was abhorrent to them; and they consider themselves much happier in their duality than are the individuals who look upon them with pity.”