Experimental Obstruction of the Mesonephric Ducts.

Abstract

In a previous paper 1 the writer showed that destruction of the growing ends of the Wolffian ducts in young chick embryos resulted in the failure of these ducts to establish connection with the cloaca. Under these circumstances, the Wolffian bodies became hydronephrotic, the cloaca failed to differentiate a urodaeal sinus, the allantois remained rudimentary, and the chicks died not later than the end of the sixth day from either lack of oxygen or a possible retention of urine. Since up to that time the allantoic fluid of normal embryos had never been analyzed by modern microchemical methods, the latter possibility could not at first be determined. But investigations begun in 1924 1 have shown that the end product of nitrogen metabolism in chick embryos is uric acid; that measurable amounts of it appear in the allantoic fluid as early as the fifth day of incubation; that it is eliminated in rapidly increasing amounts up to at least the 15th day 2 ; and that during all this time, from the 5th to the 15th day) the mesonephric tubules undergo rapid increase in both length and volume. 3

The present article deals kvith the effect of experimental obstruction of the Wolffian ducts upon the nephrogenic tissue of the embryo. In this connection it should be recalled that the rudimentary pronepliros gives rise to the IYolffian ducts; that from the 20th to the 30th sonntes these ducts are joined by the definitive mesonephric tubules; antl that after the lon-er end of each duct has given rise to the nietanephric diverticulum the latter is joined by metanephric tubules derived from the nephiwgenic tissue of somites 31 to 33 (Lillie).

In all cases in which the writer has prevented one or both Wolffian ducts from reaching the cloaca, the ureter on that side has never formed, and no metanephric tubules have developed.