G. Carl Huber 3 



•this view, the coiled urinil'erous tubules have their origin in a tissue 

 which is distinct from that of the renal anlage. Kupffer's observations 

 though faulty in inan_y respects, as later investigations have shown, must 

 be recognized as of fundamental importance, as concerns both the phylo- 

 genetic and the ontogenetic development of the permanent kidney. 



Xearly all investigators who, since the appearance of Kupffer's observa- 

 tions, have considered the question under discussion, have adopted one 

 or the other of the two views above hastily sketclied and, even taking into 

 consideration the most recent contributions to this subject, the statement 

 seems warranted that the problem under discussion is still awaiting final 

 solution. Schreiner, in a recent most admirable contribution to this 

 subject, especially as concerns the earliest stages of the development of the 

 permanent kidney, has grouped under respective heads all the more 

 important contributions dealing directly or indirectly with the develop- 

 ment of the permanent kidney, and, as it is not my purpose to enter 

 extensively into a discussion of all the literature bearing on the topic 

 under consideration since this has been undertaken by Eiickert, Herring" 

 and Schreiner, I have adopted and extended the above mentioned classi- 

 fication of Schreiner. So far as accessible to me (the exceptions I have 

 noted), I have critically reviewed the literature to which reference is 

 here made. It should, however, be stated that, while adopting such 

 a classification, I must regard it as somewhat forced. A number of the 

 contributions here referred to and especially certain of the earlier ones, 

 require interpretation through a view-point gained l)y familiarity with 

 more recent investigations and with actual preparations before a classi- 

 fication of them can be made. 



Among investigators who adhere to the view that the tubules of the 

 permanent kidney are developed by a direct budding from the epithelial 

 renal anlage derived from the Wolffian duct after the manner of other 

 tubular and of alveolar glands may be mentioned : — Eemak, 55 ; Kolliker, 

 61; Colberg, 63; Waldeyer, 70; Toldt, 74; Pyc, 75; Lowe, 79; Eibbert, 

 80: Hortoles, 81; Kallay, 85; Janosik, 85; Xagel, 89; Golgi, 89; Minot, 

 92: Haycraft, 95; Schultze, 97; Kollmann, 98; V. Ebner, 99; Gerhardt, 

 01 ; Stoerk, 01; Strahl, 02; Disse, 02; Stoerk, 04. Stoerk's fuller publi- 

 cation gives no additional data as to his view of the origin of the 

 uriniferous tubules and I assume that he still adheres to the views 

 expressed in his earlier contribution. 



The investigators who have followed Kupffer in assuming a separate 

 and distinct origin for the coiled uriniferous tubules may be arranged 

 as follows : 



Bornhaupt, 67; Thaysson, 73; Riedel, 74; Balfour, 76; Braun, 78; 



