KIDNEY IN RELATION TO WOLFFIAN BODY IN THE CHICK. 71 



Wolffian tubules is not easy to answer. I leave it open now, 

 but hope to be in a position to give a definite answer soon. 

 Now I will merely state that there are appearances in my 

 sections which incline me to the opinion that there are out- 

 growths from the Wolffian duct which, in the case of the 

 primary Wolffian tubules, are solid, but hollow in the case of 

 the secondary and tertiary tubules. 



The above description of the development of the primary 

 Wolffian tubules differs from the most recent account of 

 KoUiker^ and Fiirbringer.^ I have stated above the views 

 which these distinguished observers hold as to the develop, 

 ment. They have described perfectly correctly one stage in 

 the development of the anterior part of the Wolffian body. 

 I have often seen the appearances given by Kolliker in fig. 

 125 of his work, and have given myself a similar represen- 

 tation (fig. 1). But if I understand them correctly they 

 have given an erroneous account of the earlier development 

 of these structures. Fiirbringer says of them (p. 67) : " Sie 

 finden sich in reihenweiser Anordnung als solide Urnieren- 

 strange die von dem parietalen Peritoneum ventral und 

 medial vom WolfF'schen Gauge ausgehen. . . . Sehr bald losen 

 sich diese Urnierenstrange von dem parietalen Peritoneum 

 ab undliegennun als rundliche solide Zellenmassen retrope- 

 ritoneal neben dem Wolff 'schen Gauge, ein Stadium das die 

 Beobachtungen der meisten Autoren deckt." It is easy to 

 see how Fiirbringer has been misled. He has seen in trans- 

 verse sections in a fairly young chick the S-shaped strings 

 of cells (solide Urnierenstrange) in connection with the peri- 

 toneal epithelium. He has also seen in an older chick the 

 Wolffian blastema of the posterior region of the Wolffian 

 body (rundliche solide Zellenmassen). Both these observa- 

 tions I can entirely confirm. But apparently he has not 

 examined the condition of these structures at an earlier 

 stage, assuming that they originate as solid outgrowths of 

 the peritoneal epithelium. This assumption my observa- 

 tions prove to be unwarranted. 



The older observers (see above) were quite correct in their 

 statements of the origin of the Wolffian tubules, as struc- 

 tures developed in the intermediate cell mass, independently 

 of the Wolffian duct, and later acquiring an opening into it. 



Waldeyer's^ statement that the Malpighian body thu 

 develops, the rest of the Wolffian tubule developing as out- 

 growths from the Wolffian duct, is in my opinion erroneous. 

 For if there be an outgrowth from the Wolffian duct it 

 does not give rise to the whole tubule, exclusive of the 

 ' Loc. cit. ' ' Morph. Jahrbuch,' Bd. 4. » Loc cit. 



