DISEASES OF THE URINARY ORGANS. 135 



favor the formation of stono, ot" taiirocholic acid, ami other bodies 

 that tend ^vhen in excess to destroy the hh)()d «rl()l)ules and to cause 

 iiritation of the kidneys by the resultin^j; henio«j:b)bin excreted in the 

 mine, and of «2^1yco<;en too abuntbmt to be burned up in the system, 

 which induces sacciuirine mine (diabetes). Any disorck'r leadin*^ to 

 impaired functional activity of the hin<?s is causative of an excess of 

 bipi)urie acid and allied iiodies, of oxalic acid, of su<rar, vtc. in tlie 

 urine, which irritate the kiilneys, even if they do not produce solid 

 depasits in the urinary passages. Diseases of the nervons system, 

 and notably of the base of the brain and of the si)inal cord, induce 

 various urinary disorders, jn-ominent anion*; Avhich are dial)etes, 

 chylous urine, and albuminuria. Certain affections, with imperfect 

 nutrition or destructive waste of the bony tissues, teiul to cliar<xe tlio 

 urine with phosphates of lime and magnesia and endanger the 

 formation of stone and gravel. In all extensive inflammations and 

 acute fevers the licjuids 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 i-etained waste products poison the system at huge. 



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 li<iuid 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 foimd in mag- 

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

 e^pecially injurious to the kidneys, as are also various cryptogams, 

 whether in musty hay or oats. The kidnej'S 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 damj) 

 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 J ounces, is shaped like a Fiend i 

 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 i)arts — (a) the 

 exteinal (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) tul)es and on the 

 surface of the sinuous, secreting tubes leading from the sacs inward 

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



