234 



THE CAT. 



[chap. VIII. 



the expanded terminations of the contorted nriniferous tubes. Each 

 such corpuscle contains a bunch of minute looped capillary vessels, 

 forming- what is called a r/lonicrulus (Fig. 110, //), and has itself a 

 most delicate epithelial lining contrasting with the thick spheroidal 

 lining of the nriniferous tubes. A small artery enters each glome- 

 rulus, and there breaks up into a number of minute branches ending 

 in a capillary network, whence a small vein (Fig. Ill, c') arises, 



Fig. no. — SKMI-mAGKAMMATIC REPRESENTATION 

 OP A MaLPIGHIAN liODY IN ITS RELATION 

 TO THE UrINIFKROUS TUBE. MAGNIFIED 

 :iOO DIAMETERS. 



((. Ciii).snlii (if the Utalpigliiaii Ixuly rontiinimis 

 with (h), tlic iiieiiibraiia pruinia uf tlic coikil 

 urinirerdiis tube. 



c. Kiiithelium iif tlic M:iliii;^hiari lioily. 



il. Eiiithclium of tlii; uiiiiiffruus tube. 



c. Di'tachud (,']>ithuliuiii. 



/. Atlerelit vessel. 



(J. Kfl'creiit vessel. 



h. Convoluted vessels of the glomerulus. 





I 

 'I 





Fig. 111. — PlACRAM SHOWING THE RELATION 

 OF 'I'llK MAI.rialllAN JJliDV TO TIUv UUINI- 



FERoi's Ducts and Blood-vessels. 



(I. One of (he arteries. 



(('. A branch jiassiug to the glomerulus. 



c. Cajisule of the Malpighiali body. 



t. Uriniferoiis tubes. 



(', c. Kflereiit vessels, wliieli subdiviile in the 

 jilexusO)), suiroimdiiig the tube, and liiially 

 teriiiinate in the branch of the renal vein (f). 



which leaves the glomerulus, and breaks up into another netAvork 

 or plexus (Fig. Ill, |;) of capillaries surrounding the tubules, 

 whence arise other veins, which convey the blood ultimately to the 

 renal vein. Thus we have in the kidney a multitude of minute 

 special circulations, each of which is analogous to the portal system 

 or that of the coronary vessels of the heart. 



The I'UKcTioN of the kidney is, as has been said, to remove 

 nitrogenous waste products and salts from the blood by the secretion 

 and excretion of urine, and it thus supplements the action of the 

 lungs by the removal of matters which escape the action of the 

 pulmonary organs. The blood comes, as wc have seen, to the 

 kidneys direct from the abdominal aorta, and is therefore as pure 

 as wlien it leaves the left ventricle. In circulating through the 

 kidney it is still further ])urified, namely, from its nitrogenous waste 

 matters, and it also loses more carbonic acid by the formation of 

 urine, than it acipiircs by any wear and Icar of the tissues of the 

 gland. Thus the blood which leaves the kidney is at its maximum 



