62 



(tlie uorinal protluct of tissue cliango), favor the formation of stone, 

 of taurocliolic acid, and otlier bodies that tend, when in excess, to 

 destroy the blood globules and to cause irritation of the kidneys by 

 the resulting- haemoglobin excreted in the urine, and of glycogen too 

 abundant to be burned up in the system, which induces saccharine 

 urine (diabetes). Any disorder leading to impaired functional activ- 

 ity of the lungs is causative of an excess of hippurie acid and allied 

 bodies, of oxalic acid, of sugar, etc. , in the urine, which irritate the 

 kidneys even if they do not produce solid deposits in the urinary pas- 

 sages. Diseases of the nervous system, and notably of the base of 

 the brain and of the spinal cord, induce various urinary disorders, 

 prominent among which are diabetes, chylous urine, and albuminuria. 

 Certain affections, with imperfect nutrition or destructive waste of 

 the bony tissues, tend to charge the urine with iihosphates of lime and 

 magnesia, and endanger the formation of stone and gravel. In all 

 extensive inflammations and acute fevers the liquids of the urine are 

 diminished, while the solids (waste products), which should form the 

 urinary secretion, are increased, and the surcharged urine proves 

 irritant to the urinary organs or the retained waste products poison 

 the system at large. 



Diseases of the heart and lungs, by interfering with the free onward 

 flow of the blood from the right side of the heart, tend to throw that 

 liquid back on the veins, and this backward pressure of venous blood 

 strongh- tends to disorders of the kidneys. Certain poisons taken with 

 the food and water, notably that found in magnesian limestone and 

 those found in irritant diuretic plants, are especially injurious to the 

 kidneys, as are also various cryptogams, vrhether i^resent in musty hay 

 or oats. The kidney's may be irritated by feeding green vegetables 

 covered with hoar-frost or by furnishing an excess of food rich in phos- 

 phates (wheat bran, beans, pease, vetches, lentils, rape-cake, cotton- 

 seed cake) or bj^ a privation of water which entails a concentrated 

 condition and high density of the urine. Exposure in cold rain or 

 snow storms, cold draughts of air, and damp beds are liable to fur- 

 ther disorder an already overworked or irrital)lo kidney. Finally, 

 sprains of the back and loins may cause bleeding from the kidneys 

 or inflammation. 



The right kidnej^, weighing 23^ ounces, is shaped like a French bean, 

 and extends from the loins forward to beneath the heads of the last 

 two ribs. The left kidnej- (Plate lY) resembles a heart of cards, and 

 extends from the loins forward beneath the head of the last rib only. 

 Each consists of three distinct i^arts, («)the external (cortical) or vas- 

 cular part, in which the blood-vessels form elaborate capillar}^ networks 

 within the dilated globular sacs which form the beginnings of the secret- 

 ing (uriniferous) tubes and on the surface of the sinuous secreting 

 tubes leading from the sacs inward toward the second or medullary 

 l^art of the organ; (?>) the internal (medullary) part, made up in the 



