76 BUIiEAU OF AXIMAL INDUSTRY. 



the urine; of an excess of hippuric ticid and allied products, which being 

 less soluble than urea (the normal product of tissue change), favor the 

 formation of stone, of taurocholic acid and other bodies that tend, 

 "when in excess, to destroy the blood globules and to cause irritiition 

 of the kidneys by the resulting hemoglobin excreted in the urine, and 

 of gbrcogen too abundant to be burned up in the system, which induces 

 saccharine urine (diabetes). Any disorder leading to impaired func- 

 tional activity of the lungs is causative of an excess of hippuric acid 

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

 irritate the kidneys even if thej'^ do not produce solid deposits in the 

 urinary passages. Diseases of the nervous system, and notably of the 

 base of the brain and of the spinal cord, induce various urinary dis- 

 orders, prominent among which are diabetes, ch^'lous urine, and albu- 

 minuria. Certain affections, with imperfect nutrition or destructive 

 waste of the bony tissues, tend to charge the urine with phosphates 

 of lime and magnesia., and endanger the formation of stone and gravel. 

 In ail 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 

 strongly 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 cr3'ptogams, whether present in musty hay 

 or oats. The kidneys 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 by a privation of water which entails a concentrated 

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

 snowstorms, cold drafts of air, and damp beds are liable to further dis- 

 order an already overworked or irritable kidney. Finally, sprains of 

 the back and loins may cause bleeding from the kidneys or inflamma- 

 tion. 



The right kidney, weighing 23i ounces, is shaped like a French bean, 

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

 two ribs. The left kidney (Plate IV) resembles a heart of cards, and 

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

 Each consists of three distinct parts — (a) the external (cortical), or vas- 

 cular part, in which the blood vessels form elaborate capillary networks 

 within the dilated globular sacs which form the beginnings of the 

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



