Thomas Fienus, a physician and a professor in the University of Louvain, in 1620 published a book[25] in which he held that the soul is infused about the third day after conception, and his argument for the early advent of the soul is very sound. As a result of Fienus's revolutionary argument, Florentinus in 1658 brought out a book at Lyons, called De Hominibus Dubiis Baptizandis, in which he held that no matter what the age of the aborted fetus, if it could be differentiated from a mole it should be baptized. This book was brought before the Congregation of the Index. The congregation did not condemn the book, but the author was forbidden to teach that his doctrine holds sub gravi. The book went through many editions and was approved by the faculties of the principal universities and the theologians of the leading religious orders.
Zacchias, chief physician to Innocent X., in 1661 published his Questiones Medico-Legales, and in this he maintained that "the human fetus has not at any time any kind of soul other than a rational, and this is created by God at the first moment of conception, and is then infused."[26] By 1745 the opinion of Zacchias as to the moment life begins was virtually general among physicians, and has since remained the doctrine of physicists. Modern discoveries by biologists have confirmed the fact that human life exists in the impregnated ovum exactly as it does in all stages of life, and no scientist holds any other opinion. There are, however, a few moralists at the present day who incline to the old Thomistic doctrine or to modifications of it.
St. Alphonsus Liguori[27] was a follower of the Thomistic opinion. He affirmed: "They are wrong that say the fetus is animated at the instant of conception, because the fetus certainly is not animated before it is formed, as is proved from Exod. xxi: 22, where in the Septuagint version we find: 'He that strikes a gravid woman and causes abortion, will give life for life if the child was formed; if it was not formed, he will be fined.'" This argument by St. Alphonsus is invalid apart from any facts that may bear upon either the Thomistic or the modern opinion concerning the quickening of the fetus. The text from the Septuagint Exodus is (1) too doubtful in itself to be the basis of any argument; but (2) even if it were authentic just as it stands, the conclusion St. Alphonsus draws from it is not warranted by the premises. The Septuagint text differs from the Vulgate and the Hebrew texts. The Vulgate has it thus: "Si rixati fuerint viri et percusserit quis mulierem praegnantem, et abortum quidem fercerit, sed ipsa vixerit, subjacebit damno quantum maritus mulieris expetierit et arbitri judicaverint; sin autem mors fuerit subsecuta, reddit animam pro anima, oculum pro oculo, dentem pro dente, manum pro manu, pedem pro pede, adustionem pro adustione, vulnus pro vulnere, livorem pro livore."[28] This version has nothing whatever to say about the foetus formatus or non formatus; it is merely an application of the Semitic Lex Talionis, and the form of the law is clearly corrupt and inaccurate.
The passage quoted by St. Alphonsus as that of the Septuagint is not exact even as the Septuagint has it. The full text is: "If two men fight, and one strike a woman that hath [a child] in the womb, and her babe come forth not yet fully formed,[29] in a fine he shall be mulcted; whatsoever the husband layeth upon him he shall give according to decision [i.e., of the judges]. But if it [the babe] be fully formed he will give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe."
This is (1) evidently nothing but an application of the Lex Talionis, with no thought whatever of the biological animation, as such, of the fetus. It means that if a fully formed fetus be aborted, either no real damage is done, as such a child is viable; or the formed child may be maimed, and then the Lex Talionis is to be applied. If the fetus is not fully formed it is not a fit subject of the Lex Talionis since it cannot lose an eye, a tooth, and so on, because it lacks these organs and therefore the law of retaliation is not to be enforced.
(2) Suppose, however, the writer of the text as the Septuagint has it did think with St. Alphonsus that the formed fetus is animated, and the unformed is not animated, even then the conclusion drawn by St. Alphonsus is not warranted by the text. The laws of Exodus do not teach embryology, physiology, or any other part of physical science; and no authority worth a hearing holds that the Scriptures were intended to be infallible treatises on obstetrics or astronomy. Like the other parts of the Bible, the laws of Exodus presuppose the unscientific biological, astronomical, and other physical notions of the time in which they were written—the moral truth is the matter the Scripture is dealing with; there no inaccuracy is to be found. St. John (1:13) speaks of those who believe in Christ's name, "Qui non ex sanguinibus, neque ex voluntate carnis, neque ex voluntate viri, sed ex Deo nati sunt." Here he expresses the contemporary notion, which is also the Thomistic opinion, that men are generated from the specialized blood of their parents. He was interested solely in conveying the truth that those who received Christ were regenerated by him, not through heredity; and he does so, although the biology is inexact. If St. Alphonsus's conclusion is valid as from the text of Exodus, then men are generated ex sanguinibus, and so on indefinitely.
The Massoretic text of this passage seems to be the best preserved: "If men fight, and one hurt a woman who is with child, and her child come forth, yet there is no mischief, he [who struck her] shall be mulcted in a fine; whatsoever the husband of the woman layeth upon him he shall pay according to the judges. But if there be mischief, then he shall give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe." Here the Hebrew text follows the Lex Talionis exactly. If, in a brawl, a man's pregnant wife is struck and abortion results, the offender pays the penalty. If the abortion does not kill or maim the child, the culprit is fined by the Sanhedrim; if the child is killed or maimed, then the penalty is according to the Lex Talionis. In the Hebrew text also there is no mention of a distinction between a foetus formatus and non formatus.
Whether the fetus is animated at conception or some time later, there is no foundation whatever for the notion that the female is quickened later than the male. As was said before, Aristotle held that the human male fetus is animated at the fortieth day, the female at the ninetieth day, and the old moralists accepted his statement. At the fortieth day, however, no one can differentiate sex unless the microscope is used, and this particular use of the microscope is altogether modern—the knowledge requisite for such use was not in existence sixty years ago. At the twentieth day, with the microscope and a stained specimen, a biologist can recognize whether the primordial ova are present or absent and thus determine sex. Only at the eighty-fourth day can sex now be differentiated without the aid of the microscope, but then the embryo must be dissected: nothing can be told from its external appearance. Sex can first be distinguished by the external appearance only at about the one hundred and twelfth day, the end of the fourth month of gestation. Therefore when Aristotle said the male fetus is animated at the fortieth day, and the female at the eightieth or ninetieth day, he was romancing.
The question, then, narrows to this: Is any human fetus animated immediately at conception, or from forty to eighty days after conception? The reason given by the followers of Aristotle for deferring animation is that the vital principle requires organs in the receptive material, but the embryo in the early stages, they say, lacks these organs. This notion, however, as to the lack of organs is altogether erroneous, and the rational soul enters the embryo in the oval stage, immediately after the pronuclei unite: there is organization in that stage of human life sufficient to receive the substantial form or soul. We do not know how long after insemination the pronuclei unite, but the proposition here is that as soon as they unite the human soul enters. Fecundation usually occurs after a menstruation, but not necessarily so; the spermatozoön may live in the tube for seventeen days awaiting the ovum.
The human body is made up of billions of microscopic living cells, all of which are derived by fission and differentiation from the two original single germ-cells, the ovum and the spermatozoön. Some nerve-cells have long processes running along the white fibres through the