494 PHILOSOPHICAL TRANSACTIONS. [ANNO 17 QQ, 



fluence on the constitution of the female ; and that, when the ovaria are imper- 

 fectly formed, or when testicles are substituted for them, though the external parts 

 are decidedly female, the person may grow up, deprived of that feminine character 

 which the constitution would have acquired, if the ovaria had been capable of pro- 

 ducing their influence on the body. To this cause may be attributed the unnatural 

 bias which some women have shown, to pass through life in the character of men. 

 The circumstance of some women, after the time of breeding is over, at which 

 period the influence of the ovaria may be considered as lost to the constitution, 

 approaching nearer to the male in appearance, and acquiring a beard ; also the 

 female pheasant and duck *, in several instances, at the same period of their life, 

 acquiring the feathers which distinguish the male, so as to be mistaken for males, 

 is in favour of such an opinion. 



The histories of monsters which have superfluous parts, as that of the child 

 with the double head -)~, and all others of the same kind, lead to the opinion of 2 

 or more foetuses having been contained in 1 ovum, similar to 2 yolks in 1 egg ; 

 and that, from some circumstances having taken place in utero, certain parts of 1 

 of the foetuses were prevented from coming to perfection, and were absorbed ; while 

 those that remained became connected to the other foetus. When monsters are. 

 imperfect, there is no difficulty in accounting for any organ, or other structure, 

 not having been completely formed ; but, that the ovaria should be wanting, and 

 their place supplied by testicles, is not to be explained on the same principle. The 

 testicles being substituted for the ovaria, and the ovaria themselves entirely wanting, 

 is probably the most curious circumstance that is met with, in the structure of 

 these hermaphrodites ; and as many important discoveries in the animal economy 

 have been suggested from the examination of monstrous productions, it naturally 

 leads to the inquiry, whether there is any thing in the original formation of the 

 parts, which can account for so strange an occurrence. The only mode in which 

 it can be explained, as far as I am able to judge, appears to be the following. By 

 supposing the ovum, previous to impregnation, to have no distinction, but to be 

 so formed as to be equally fitted to become a male or female foetus ; and that is 



* The following account of a duck of this kind was sent me by Mr. Rumball, surgeon, at Abingdon, 

 in Berkshire. The duck was bred by Mr. Cator, of Norwood, in Surrey, in the year 1781. It conti- 

 nued to lay, and to hatch its young, till the year 1789 ; when the curled feathers, peculiar to the drake, 

 made their appearance in its tail. From this period, she not only left off laying, but frequently attempted 

 to tread the other ducks, both in the water, and on the ground j and they courted her in return. This 

 was particularly observed on the 19th of August, 1791, when she trod a duck in the water, and fell off 

 on her side, as drakes usually do ; and they both began washing themselves immediately after, as is cus- 

 tomary on these occasions. She never afterwards suffered a drake to come near her. Though the plu- 

 mage changed, the voice continued the same, which is very different from that of the drake. This cir- 

 cumstance first attracted Mr. Rumball's notice, and made him doubt of its being really a drake. On 

 the 14th of Oct. 1793, at the request of Mr. Rumball, this duck was sent to Mr. Hunter, and died on 

 the 18th, 2 days after Mr. Hunter's death. On examination, the organs of generation were those of a 

 perfect duck. The skin is stuffed, and preserved in Mr. Hunter's collection. — Orig. 



| Phil. Trans, vol. 80, p. 296, and vol. 89, p- 28.— Orig. 



