AUTHOR S ABSTRACT OF THIS PAPER ISSI ED 

 BY THE BIBLIOGRAPHIC SERVICE, OCTOBER 27 



THE COURSE OF THE WOLFFIAN TUBULES IN 

 MAMMALIAN EMBRYOS 



FREDERIC T. LEWIS 



Harvard Medical School, Boston, Massachusetts 



THIRTEEN FIGURES 



In early stages, when the Wolffian tubules are so short that 

 they may be cut throughout in single sections, their course from 

 glomerular capsule to Wolffian duct has been thoroughly studied. 

 Kolliker, Mihalkovics, Meyer, Schreiner, and others have de- 

 scribed their S-shaped form. But in older embryos the length 

 and sinuosities of the tubules are such as to require reconstruc- 

 tion. "Nevertheless," as Nicolas wrote in 1891, "it can be 

 recognized without too great difficulty that their general orienta- 

 tion has remained unchanged — they have merely elongated and 

 folded capriciously in different planes." The idea of capricious 

 folds is well illustrated in the single reconstruction of a tubule 

 from a human embryo of 10.2 mm., published by Kollmann, 

 and many times reproduced. But Felix records that he has 

 "studied two hundred models of mesonephric tubules from the 

 most different stages of development," and in none of them has 

 he found "any coiling of the tubule." Consequently he infers 

 that Kollmann's model must represent 'a very exceptional rarity' 

 — a conservative and accurate conclusion. The only change ob- 

 served by Felix after the tubule has become S-shaped occurs near 

 the junction of the middle and distal segments of the S (distal 

 meaning toward the Wolffian duct) , and consists in the formation 

 of "a loop directed either cranially or caudally." Unfortunately 

 Felix has not figured in detail any of the late stages included 

 among the two hundred tubules modeled, presumably from 

 human embryos, so that Kollmann's drawing appears to occupy 

 the field alone. 



423 



THE AMERICAN JOURNAL OP ANATOMY, VOL. 26, NO. 3 



