WOLFFIAN BODIES. 



657 



Fig. 2 7. 



the Wolffian bodies. (Fig. 247.) As the kidneys, however, subse- 

 quently enlarge, while the Wolffian bodies diminish, the propor- 

 tions existing between the two organs are 

 reversed ; and the Wolffian bodies at last 

 come to be mere small rounded or ovoid 

 masses, situated on the anterior surface 

 of the kidneys. (Figs. 248 and 249.) The 

 kidneys, during this period, grow more 

 rapidly in an upward than in a downward 

 direction, so that the Wolffian bodies 

 come to be situated near their inferior 

 extremity, and seem to have performed 

 a sliding movement from above down- 

 ward, over their anterior surface. This F(KTAL Pl0t one and B balf 

 apparent sliding movement, or descent inrhPH lon *- From a "P^imea in 



P , _ Tr . , ,. . . . . the author's possession. 1. Wolffi.. a 



of the \\ olffian bodies, is owing entirely body. 2 Kidney, 

 to the rapid growth of the kidneys in an 

 upward direction, as we have already explained. 



The kidneys, during the succeeding periods of foetal life, become 

 in their turn very largely developed in proportion to the rest of the 

 organs ; attaining a size, in the foetal pig, equal to 7 ' ? (in weight) 

 of the entire body. This proportion, however, diminishes again 

 very considerably before birth, owing 

 to the increased development of other 

 parts. In the human foetus at birth, 

 the weight of the two kidneys taken 

 together is T g that of the entire 

 body. 



Internal Organs of Generation. 

 About the same time that the kidneys 

 are formed behind the Wolffian bodies, 

 two oval-shaped organs make their 

 appearance in front, on the inner side of 

 the Wolffian bodies and between them 

 and the spinal column. These bodies are 

 the internal organs of generation ; viz., 

 the testicles in the male, and the ovaries 

 in the female. At first they occupy 



precisely the same situation and present precisely the same appear- 

 ance, whether the foetus is afterward to belong to the male or the 

 female sex. (Fig. 243.) 

 42 



Fig. 248. 



INTERNAL GROANS OF GENE- 

 RATION, &c ; in a foetal pig three 

 inches long. From a specimen in the 

 author's possession. 1, 1 Kidneys. 

 2,2. Wolffian bodies. 3,3. Internal 

 organ* of generation ; te^ticl^s or 

 ovaries. 4. Urinary bladder turned 

 over in front. 5. Intestine. 



