CAUSES OF RERMAFIIROOITIC MALFORMATION.
As yet we possess very little accurate know ledge either in respect to the mode in which the determining causes of hermaphroditic mal formation act, or the nature of these causes themselves.
Most of the varieties of spurious herma phroditism may, as we have just explained, be traced to an arrest in the development of the sexual organs at one or other period of their evolution, in consequence of which some of those types of structure in these parts which were intended to be temporary and transitory only, are rendered fixed or permanent in their character. Our knowledge of the more imme diate causes of such arrested development in these and in other individual parts and organs of the body, is as yet extremely limited, and for the discussion of it we must refer to another part of the present work, (see article Mots sraosrrt ns). We may, however, in reference to the particular forms of arrested development observed in hermaphroditism, remark that in consequence of the great influence which, as we have already pointed out, is exercised by morbid states of the ovaries and testicles, in retarding or preventing the evolution of the sexual apparatus and characters after birth, it has been suggested with considerable probabi lity by Meckel and Isidore St. Hilaire,, ' that in their ultimate analysis certain cases of her maphroditic malformation may be traced in the course of their causation to morbid influences exercised in the early embryo, at a period more or less near to conception: upon the ovaries or testicles, or upon those organs of a neuter or yet undetermined sex which after wards assume the structure of one or other of these bodies. Further, the effects which this supposed morbid influence exercises directly upon the embryonic ovaries and testicles, and indirectly through them, upon the rest of the genital apparatus, and consequently the modi fications of sexual structure which it produces, may possibly be much varied according to its extent, duration, and nature, and according to the particular period of development at which it comes into action. It is evident that this ex planation of hermaphroditism can only refer to the varieties of the malformation which consist of an imperfection or deficiency in the development, and cannot apply to those in stances in which there is a superaddition of sexual organs. If, however, we can once satisfy ourselves that any set of cases whatever are traceable to a morbid action affecting the testicles or ovaries of the early embryo, our investigations into the causes of these cases will necessarily be much simplified, for our inquiries would be reduced from a vague and indefinite search after the production of a num ber of anomalies of structure affecting several different organs at the same time, to an attempt to trace out the nature of those morbid condi tions to which the embryonic testicles and ovaries were subject, and which were capable of so far changing the structure and action of these organs as to give rise to the effects in question. Of the diseased states, however, to which the reproductive and other organs of the system are liable during the progress of their early development, we at present know little or nothing, although in the investigation of this subject a key, we believe, may possibly be yet found to the explanation of many of those malformations to which different parts of the body are subject.
Osiander• and have suggested that the variety of spurious hermaphroditism which consists of a division of the peri mum in the male, may be produced me chanically in the embryo by the prxterna tural accumulation of fluid in the urinary canal, on account of an imperforate state of the urethra, and the consequent distension and ultimate rupture of the urethra, &c. From cases published by Sandifort, Howship, Hil lard, and many others, we are now fully aware of the fact that all the urinary canals of the foetus in utero are occasionally found morbidly distended with a fluid, which, according to the interesting observations of Dr. Robert Lee,/ would appear to possess the more character istic qualities of urine. We have dissected one case in which the dilated fittal bladder was as large as an orange, and have seen in the Anatomical Museum of Dr. William Hunter at Glasgow the preparation of another instance in which the bladder of a full-grown foetus was dilated to the size of that of the adult subject. In one case mentioned by Dr. Mer riman, the distended organ contained half a pint of urine,• and in another detailed by Mr. learn it was capable of containing as much as two quarts of fluid.t It is not impossible that the causes in ques tion,—namely, the obliteration of the urethra and the consequent distention of all the urinary passages, and probably also of the sexual canals communicating with these passages,— may occasionally produce in the male embryo a re-opening of the perinwal fissure, giving thus to the external parts the appearance of a female vulva, and perhaps at the same time may lead to the retention and imperfect development of the testicles by the distention of their ducts, and the unusual compression to which these organs may be subjected. Indeed we have satisfactory evidence, in a few instances, that such a cause may have been in operation, by our detecting the other acknowledged effects of the urinary accumulation in question,—such as preternaturally dilated ureters, and a cystic form of the infundibula of the kidneys, as in a case of hermaphroditism given by Mayer, in a human foetus,/ in the kid described by IIaller,§ and in the child whose case we have already quoted from Steghlener. (See trans verse hermaphroditism.) At the same time the total absence of these collateral proofs in most other cases of hypo spadias, our knowledge of the fact that the perimal aperture is in some cases never shut, and the difficulty of conceiving the possibility of its being re-opened when once it is firmly closed, are perhaps sufficient to skew that the cause or causes alluded to produce in but few if any instances the effect here attributed to them.