SECRETION OF URINE. 



635 



:o 



A section of one of the Pyramids of Malpighi, and of its corresponding cortical substance, as seen 

 under the microscope ; 1, portion of the surface of the kidney ; 2, from this figure up to 1, is the cortical 

 substance of the kidney : 3, from 2 to this number is the tubular portion ; 4, the foveola j 5, 6, arteries 

 and veins ramifying through the kidney ; 7, arteries to the acina of the kidney ; 8, capillary extremities 

 of veins anastomosing with corresponding arterioles; 9, tortuous extremities of the arteries directed 

 into the interior of the gland ; 10, bases of the cones of the cortical and pyramidal substance of the kid- 

 ney ; from 10 to 4 is a collection of these cones ; 11 , the envelop of the cortical layer ; 12, prolongations 

 of the tubular portion ; 13, tortuous tubes, or those of Ferrien ; 14, straight tubes, or those of Bellini ; 15, 

 vessels which wind between them ; 16, course of the uriniferous lubes in the tubular portion ; 17, the 

 matter between these tubes j 18, bifurcation of the straight tubes ; 19, sections of these tubes ; 20, their 

 orifices.] 



opinion, all the free extremities of the tubuli uriniferi thus include Corpora Malpighiana ; 

 and the appearance of coecal terminations, such as those represented at a and c, Fig. 246, he 

 regards as an optical illusion, caused by a change in the direction of the tubuli, which occa- 

 sions them to dip away suddenly from the observer. 



