In the preceding observations we have pro ceeded upon the opinion commonly received by physiologists, of the fundamental unity of sex among all individuals belonging to the higher orders of animals ; or, to express it otherwise, we have assumed that each individual is, when normally formed, originally furnished with elemental parts capable of forming one set of sexual organs only. We do not here stop to inquire whether this single sexual type is, in all embryos, originally female, as main tained by Itosenmiiller, Meckel, Blainville, Grant. and others; or, of a neutral or inter mediate character, as supposed by the St. Ililaires, Serres, Ackermann, !tome, &c., and as we are certainly ourselves inclined to believe it.* On this subject, however, a physiological doctrine of a different kind has been brought forward by Dr. Knox, and this doctrine is so intimately connected with the question of the nature and origin of true hermaphrodites, that we must here briefly consider it.
Dr. Knox,t in conformity with some more general views which he entertains on tran scendental anatomy, is inclined to regard the type of the genital organs in man and the higher animals, as in the embryo, originally hermaph roditic, or as comprising elementary yet dis tinct parts, out of which both sets of sexual organs could be formed; and he believes that, owing to particular but unknown circum stances, either the one or the other only of these sets of elements comes to be evolved in the normal course of development. In those abnormal cases, again, in which, as in instances of double hermaphroditism, more or fewer of both sets of genital organs are present upon the same individual, he maintains that this is not to be considered as a malformation by duplicity, but is only a permanent condition of the original double sexual type, and is attri butable to the simultaneous development to a greater or less extent both of the male and female sets of sexual elements.
This doctrine of the original but temporary double sexed character of all embryos derives, perhaps, its principal support from a source to which Dr. Knox does not advert,—we mean the existence of this as the normal and perma nent sexual type in most plants and in many of the lower orders of animals. But this argument by analogy certainly cannot by any means be considered as a sufficient basis for the establish ment of so broad and important a generalization in philosophical anatomy. Dr. Knox himself seems to have been induced to adopt the idea principally because it afforded (when once assumed as a fact) a simple and elegant solution, upon the laws of development, of the occa sional occurrence of cases of true hermaphro ditism ; and in doing so, he appears to have proceeded upon the mode in which most such physiological hypotheses have been made, viz.
by drawing his premises from his deductions instead of his deductions from his premises. In the present state, however, of anatomical and physiological knowledge, Dr. Knox's hypo thesis, however ingenious in itself, is one which we cannot subscribe to ; for first, it is totally opposed to all the facts which have been ascer tained, and all the direct observations which have been made by Rathke, Meckel, Valentin, and other modern anatomists upon the sexual structure of the embryos of the higher animals in their earliest state; and, secondly, if we were to admit it merely as a probable hypothesis, it is still even in this respect equally as incapable as the old doctrine of sexual unity, of explaining all the cases of malformation by duplicity of the genital organs; for, as we have already shewn, there are some apparently well-authenticated instances of the existence of three or four testicles upon the same man, or three or four ovaries upon the same woman ; and in reference to all such cases we would, if we proceeded upon the same data and the same line of argument as those adopted by Dr. Knox, be obliged to suppose that the original sexual type is not, as lie ima gines, double only as respects the two sexes, but double even as respects each sex, and that all embryos had originally not simply the ele ments of two, but those of three or four testicles and ovaries. In explaining such cases as those to which we allude, Dr. Knox, on his own doctrine, must of necessity admit the existence of a malformation by duplicity of the sexual organs in question ; and if we grant this in regard to these instances, it is surely unne cessary to invent a particular and gratuitous hypothesis for the explanation of the analogous anatomical anormalities observed in hermaph roditism. At present we must, we believe, merely consider the occurrence of anomalous duplicity of the sexual organs, and of various other individual parts of the body, as so many simple empirical facts, of which we cannot, in the existing state of our knowledge, give any satisfactory explanation, or, in other words, which we cannot reduce to any more simple or general fact; though from the success which has attended the labours of many modern investigators in this particular department of anatomy, it seems to us not irrational to hope that ere long we may he enabled to gain much new light upon the question of double her maphroditism and the whole subject of mal formation by duplicity.