90 



THE KIDNEYS, BY C. LUDWIG. 



the free extremities of their necks are in contact, a space must 

 necessarily intervene where the belly is continuous with the neck. 

 The other point relates to the mode of coalescence of the 

 collecting and chief tubules to form the ductus papillares, 

 which occasions the rounded truncated form of the papilla. 

 The mode in which this is effected may be easily understood 



Fig. 140. 



Fig. 141. 



Fig. 140. Diagrammatic representation of the mode in which the 

 tubuli uriniferi are arranged to form a primitive cone. 



Fig. 141. Coalescence of the tubuli uriniferi in the papilla. Diagram- 

 matic representation. 



from the accompanying drawing (fig. 141) of a longitudinal 

 section through a papilla. It is here seen that the tubules run 

 from all sides, in a more or less curved manner, to reach the 

 few and short papillary ducts. 



STRUCTURE OF THE WALL OF THE URINARY TUBULES. As 

 often as the tubuli uriniferi change their diameter and direction, 

 they also become altered in structure. 



The lamina of which the spherical capsule consists, so far as it 

 can be broken up, consists exclusively of a mosaic of cells closely 

 resembling those composing the wall of the blood and lymph- 

 atic capillaries; on their outer surface is a little connective 



