THE KIDNEYS. 639 



face of the kidney by delicate cellular and vascular fila- 

 ments, which are easily torn on raising it, and which are 

 traced into its substance. It preserves the form of the 

 kidney. 



On making a section of the kidney from its convex to its 

 concave portion, two distinct substances are noticed, the 

 external or cortical, and the internal or tubular. The cortical 

 forms the superficial layer, is about FIG. 206^ 



two lines in thickness, though vary- 

 ing at different points, and sends pro- 

 cesses towards the centre of the gland 

 between the tubular portion, thus 

 dividing the latter into as many 

 separate parts assuming the form of 

 distinct cones. Its color is a reddish 

 brown, and it is also called vascular 

 from the quantity of blood-vessels ^ 

 with which it is supplied. 



On being torn, a number of gran- 

 ules are seen, which seem to compose 

 the great body of the cortical portion, and are called the 

 corpora, or acini of Halpiglii. These acini exist in immense 

 numbers, and are seen as very minute, round, red points, 

 their diameter being about the tenth of a line. Their con- 

 nection with arterial branches is compared to that of ber- 

 ries with their stems. Some, among whom is the distin- 

 guished Euysch, regard the acini as consisting wholly of 

 blood-vessels, while others view them as little glandular 

 sacs for secreting the urine, around whose walls the blood- 

 vessels are ramified, and from which arise the commencing 

 uriniferous or excretory ducts. 



According to Mr. Bowman, these acini are composed of 

 capillary arteries coiled up in loops and closely compressed, 

 so as to form vascular balls, which are enclosed in dilata- 

 tions of the urinary tubes, forming capsules for each. 



FIG. 206 represents a section of the right Kidney, having the renal capsule 

 on its top. 1 Supra-renal capsule. 2 Cortical portion. 3 Medullary or 

 tubular portion. 4 Calyces. 5 Infundibula. 6 Pelvis. 7 Ureter. 



