VOL. LXXXIX.] PHILOSOPHICAL TRANSACTIONS. 4Q5 



the process of impregnation which marks the distinction, and conduces to produce 

 either testicles or ovaria, out of the same materials. The following circumstances 

 are in favour of this opinion. The testicles and ovaria are formed originally in 

 the same situation, though the testicles, even before the foetus has advanced to the 

 8th month, are to change their situation, to a part at a considerable distance. 

 The clitoris, in foetuses under 4 months, is so large as to be often mistaken for a 

 penis. Preparations to show the size of the clitoris at this age are preserved in 

 Mr. Hunter's collection ; and M. Ferrien mentions it, with a view to explain an 

 erroneous opinion which prevailed in France *, that the greater number of mis- 

 carriages between 3 and 4 months, have been remarked to be males ; which mis- 

 take arose from the above circumstance. The clitoris originally appears therefore 

 equally fitted to be a clitoris or penis, as it may be influenced by the ovarium or 

 testicle. 



In considering this subject, it is curious to observe the number of secondary 

 parts, which appear so contrived that they may be equally adapted to the organs of 

 the male or female. In those quadrupeds whose females have mammae inguinales, 

 the males have also teats in the same situation ; so that the same bag which con- 

 tains the testicles of the male, is adapted to the mammae of the female. In the 

 human species, which have the mammae pectorales, the scrotum of the male serves 

 the purpose of forming the labia pudendi of the female, and the preputium makes 

 the nymphae. The male has pectoral nipples, as well as the female ; and in 

 many infants, milk, or a fluid analogous to it, is secreted ; which proves the exist- 

 ence of a glandular structure under the nipple. This circumstance, when added 

 to the instances already related, of an hermaphrodite bull, and of wethers giving 

 suck, affords a strong presumption that the rudiments of the mammae exist in the 

 male, and in some few instances have been brought to perfection, either by an 

 original mixture of organs, early emasculation, or other changes with which we 

 are at present unacquainted. 



If it is allowed that the sex is impressed on the ovum at the time of impreg- 

 nation, it may in some measure account for the free-martin occurring when 2 

 young are to be impressed with different sexes, at one impregnation ; which must 

 be a less simple operation, and therefore more liable to a partial failure, than when 

 1 or any greater number of ova are impressed with the same sex. It may also ac- 

 count for twins being most commonly of the same sex ; and when they are of dif- 

 ferent sexes, it leads us to inquire whether the female, when grown up, has not in 

 some instances less of the true female character than other women, and is not inca- 

 pable of having children. It is curious, and in some measure to the purpose, that in 

 some countries, nurses and midwives have a prejudice, that such twins seldom breed. 

 This view of the subject throws some light on those cases where the testicles are 

 substituted for the ovaria ; since, whenever the impregnation fails in stamping the 

 ovum with a perfect impression of either sex, the part formed will neither be an 

 * Mem. de l'Acad. Royal des Sciences de Paris, 1767, P' 330. — Orig. 



