PARTS CONCERNED IN REPRODUCTION. 243 



does at times occur, and may, on this view, be explained in 

 accordance with the general principles of teratology. Con- 

 genital malformations are generally the result either of 

 defect or excess of development, or of the irregular associa- 

 tion of both influences ; and the latter is exactly the 

 condition calculated to induce such a monstrosity, on the 

 hypothesis in question. The most common form of inter- 

 mixture is probably the development of male organs on one 

 side, and female on the other a monstrosity which has 

 been observed in Fishes and Insects.* In the latter, it 

 reveals itself by a corresponding disparity in the external 

 characters of sex, as in the markings of the wings of Butter- 

 flies. ( But there are not wanting instances of a true 

 intermixture of male and female organs on the same side of 

 the body.i Such cases afford a strong argument in favour 

 of the original co-existence of the organs of both sexes as 

 a normal arrangement, for otherwise we must first assume 

 the co-existence of another malformation viz., the dupli- 

 cation of the organs on one or both sides and then their 

 sexual development in opposite ways ; a view which is 

 quite opposed to the general rule, that in double monsters 

 the two individuals are always of the same sex. 



It does not appear, however, that the speculation of Dr. 

 Knox is borne out by the embryonic development of the 

 parts in the higher animals, in which alone the point has 

 been carefully examined. It is true it cannot be said either 

 to be disproved by this test ; only there is an entire absence 



* Siebold's Comparative Anatomy, 348, note 1. 



Dr. Simpson, on Hermaphroditism. Obstetric Works, Vol. II., 

 pp. 242-304 a reprint, with some additional cases and remarks, from an 

 article in the Cyclopaedia of Anatomy and Physiology, Vol. III. 



f An illustration of this bi-sexual livery is given in Humphrey's Butter- 

 fly Vivarium, page 142, and plate II. fig 6. 



J Simpson Op. Cit., pp. 280-339. 



Dr. Blackman and Dr. W. J. Burnett, in the American Journal of the 

 Medical Sciences, N. Ser., Vol. XXVI., pp. 63-367. 



M2 



