DISEASES OF THE UBINABY OEGANS. 135 



favor the formation of stone, of taurocholic acid, and other bodies 

 that tend when in excess to destroy the blood globules and to cause 

 irritation of the kidneys by the resulting hemoglobin 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 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 they 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 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 phosphates 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 strongly tends to disorders of the kidneys. Certain 

 poisons taken with the feed and water, notably that found in mag- 

 nesian limestone and those found in irritant, diuretic plants, are 

 especially injurious to the kidneys, as are also various cryptogams, 

 whether in musty hay or oats. The kidneys may be irritated by 

 feeding green vegetables covered with hoar frost or by furnishing 

 an excess of feed rich in phosphates (wheat bran, beans, peas, vetches, 

 lentils, rape cake, cottonseed cake) or by a privation of water, which 

 entails a concentrated condition and high density of the urine. Ex- 

 posure in cold rain or snow storms, cold drafts of air, and damp 

 beds are liable to further disorder an already overworked or irritable 

 kidney. Finally, sprains of the back and loins may cause bleeding 

 from the kidneys or inflammation. 



The right kidney, 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 kidney (PI. VIII) 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 vascular 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 tubes leading from the sacs inward 

 toward the second, or medullary, part of the organ; (6) the in- 



