The development of the kidney in the rabbit. 



289 



rial for the study of the Wolfiian body is somewlial limited 1 anti- 

 cipate that my probability of error is considerable, and wish that 

 these results should be taken as suggestions only.^) 



Diagrammatic view 



of the Kidney of a 



six days chick. 



The Kidney of a chick of six days. 



The earliest specimen of the rabbit's Kidney that 1 possess is one 

 from an embryo of twelve days. The first trace of this organ appears 

 on the eleventh day, when, according to Kölliker, 

 the ureter may be traced up to the cells of the 

 Kidney blastema which has at this period formed 

 a recognisable mass behind the Wolflan body. In 

 my own specimen the tubules have just begun to 

 form, and there are six of them in each Kidney 

 blastema. I have in the chick of the sixth day 

 sections which shew the ureter passing to the 

 Kidney blastema, and budding off into two tubules: 

 this may therefore be taken as giving a stage 

 even earlier than that of the 12 day embryo 

 rabbit, and may now shortly be described. 



Longitudinal sections of this embryo per- 

 mit one to trace the ureter from its junction 

 with the Wolffian duct up to the Kidney 

 blastema into which it passes for some little 

 distance, its lumen, its basement membrane 

 and short columnar cells may be, all of 

 them, traced for a little distance with in 

 the blastema, in which it terminates by an 

 expansion whose cavity is several times the 

 diameter of the lumen of the ureter. This 

 cavity, I take it, is the first of a series of 



cavities which are found eventually in the ^ . ,. , . 



Longitudinal view of part 



cortex of the Kidney and which in the rabbit of the Kidney of a six days 



play an important part in the development '^''^: ^^' ^'f '^ "^f^ !" 

 ^ "^ ^ ^ ^ a primary renal vesicle A. 



of the tubules. I shall term these structures which is about to divide 



into two.* 



xii. 19 



^) Anat. Anzeiger. 1894. 

 Internationale Monatsschrift für Anat. u. Pliys. 



