Page:The Works of William Harvey (part 1 of 2).djvu/630

 the object of respiration be really to "cool" the animal, shall be discussed elsewhere at greater length.

In the mean time I would propose this question to the learned—How does it happen that the fœtus continues in its mother's womb after the seventh month? seeing that when expelled after this epoch, not only does it breathe, but without respiration cannot survive one little hour; whilst, as I before stated, if it remain in utero, it lives in health and vigour more than two months longer without the aid of respiration at all. To state my meaning more plainly—how is it that if the fœtus is expelled with the membranes unbroken, it can survive some hours without risk of suffocation; whilst the same fœtus, removed from its membranes, if air has once entered the lungs, cannot afterwards live a moment without it, but dies instantly? Surely this cannot be from want of "cooling," for in difficult labours it often happens that the fœtus is retained in the passages many hours without the possibility of breathing, yet is found to be alive; when, however, it is once born and has breathed, if you deprive it of air it dies at once. In like manner children have been removed alive from the uterus by the Cæsarean section many hours after the death of the mother; buried as they are within the membranes, they have no need of air; but as soon as they have once breathed, although they be returned immediately within the membranes, they perish if deprived of it. If any one will carefully attend to these circumstances, and consider a little more closely the nature of air, he will, I think, allow that air is given neither for the "cooling" nor the nutrition of animals; for it is an established fact, that if the fœtus has once respired, it may be more quickly suffocated than if it had been entirely excluded from the air: it is as if heat were rather enkindled within the fœtus than repressed by the influence of the air.

Thus much, by the way, on the subject of respiration; hereafter, perhaps, I may treat of it at greater length. As the arguments on either side are very equally balanced, it is a question of the greatest difficulty.

To return to parturition. Besides the reasons alluded to above, viz. "the necessity for respiration and the want of nourishment," Fabricius gives another; he says, "that the weight of the fœtus becomes so great as to exert considerable pressure,