Let us not disdain to consider that state through which we have all passed; let us view human kind in the cradle; let us enquire by what degrees this delicate machine, this new-born and hardly existing body, acquires motion, consistency, and strength. The infant at its birth comes from one element into another. On emerging from its watery residence in the womb, it becomes exposed to the air, and instantly experiences the impressions of that active fluid. The air acts upon the olfactory nerves and upon the organs of respiration, and thereby produces a shock, a kind of sneezing which expands the chest, and allows the air a passage into the lungs; the vesicles of which it dilates, and the air remaining for some time becomes warm and rarified to a certain degree; after which this spring of the fibres thus dilated re-acts upon this light fluid, and expels it from the lungs. Instead of undertaking to explain the causes of the alternate motion of respiration, we shall confine ourselves to an elucidation of its effects. This function is essential to the existence of man and of several species of animals. It is by respiration that life is preserved; and when it is once begun, it never ceases till death. Yet there is reason to believe that the foramen ovale is not closed immediately after the birth; and of consequence a part of the blood may continue to pass through that aperture. All the blood cannot, therefore, at first have a communication with the lungs; and it is probable a new-born child might sustain a privation of air for a considerable time without losing its existence. Or at least the possibility of this, I once seemingly confirmed fey an experiment upon some young dogs. I put a pregnant bitch, of the large greyhound species, just as she was about to litter, into a tub filled with warm water, where after fastening her in such a manner that the lower parts were covered with some water, she brought forth three puppies, which were accordingly received into a liquid as warm as they had left. After washing them in this water, I removed the puppies, without giving them time to breathe, into a smaller tub filled with warm milk; I chose milk in order that they might receive nourishment if they required it. In this milk they were kept immersed above half an hour: and when taken out they were all found alive. They began to breathe, and to discharge some moisture by the mouth. Having allowed them to respire for half an hour, I again put them into warm milk, and left them a second half-hour; at the expiration of which two of them were taken out vigorous and seemingly no wise incommoded, but the third appeared rather in a languishing state; this I caused to be carried to the mother, which by this time had produced, in the natural way, six other puppies; and though it had been brought forth in water and had lived in milk one half hour before, and another after it had breathed, it yet received so little injury from the experiment, that it presently