Having examined the physiological principles upon which the _hydrostatic test_ is established, and explained the manner in which it is to be conducted, it remains for us to enumerate the several objections which have been urged against its validity. 1. _A fœtus may breathe as soon as its head is without the vagina, and immediately die._—This is one of the great arguments adduced by _Dr. Hunter_;[77] “a child,” says he, “will very commonly breathe as soon as its mouth is born, or protruded from the mother, and in that case may lose its life before its body be born; especially when there happens to be a considerable interval of time between what we may call the birth of the child’s head, and the protrusion of its body. And, if this may happen when the best assistance is at hand, it is still more likely to happen where there is none; that is, where the woman is delivered by herself;” and he adds, “if a child makes but one gasp, and instantly dies, the lungs will swim in water as readily as if it had breathed longer, and had then been strangled.” This opinion, however, must not be received without qualification. We admit that under such circumstances a portion of the lungs will become inflated, and therefore swim in water; but it would appear from the more precise and comprehensive views of later physiologists, that respiration is not completely performed on the first effort, but that it is a process gradually advancing to perfection; and that it will be more or less protracted according to the degree of vigour of which the infant is possessed. _Portal_ has shewn by experiments[78] that the air enters the _right_ lung sooner than the left, and that the left lobe is very often not at all dilated for several days. The same fact was observed by _Blancardi_.[79] _Dr. Hutchinson_ states that he was informed by a late physician to the Foundling-hospital at Naples, who opened daily, on an average, the bodies of ten or twelve infants, which had generally died within twenty-four hours after birth, that he hardly ever found more than a very small portion of the lungs dilated by air; this portion was frequently not larger than a walnut in its green shell, and but rarely larger than a hen’s egg, and it was commonly situate in the _right_ lung.[80] “I have seen,” continues the author above cited, “a case where the _right_ lobe, when separated from the left, sank in water, though this was the most dilated by respiration, and the infant had lived forty hours, and cried pretty strongly: but it died from suffocation by being _overlaid_, as it is popularly termed, by the mother, which had produced such an engorgement of blood in the lungs, as to counterbalance the influence which the small quantity of air they contained could have exerted on their specific gravity. A piece somewhat more than a cubic inch in volume was the greatest portion that in this case floated in water.”