212 The Farmer's Veterinary Adviser. 



tain diseases of the lungs or other conditions which inter- 

 fere with respiration. 



SiUoa enters the system as silicate of potassa in food 

 and water and especially in cyperaceaea, horsetails, oat- 

 straw, oat-meal, etc. It is displaced as silica whenever it 

 comes in contact with a stronger acid. 



Phosphates enter the system in bran, in beans, peas, 

 and the leguminous seeds generally, in oil-cake and rape- 

 cake, or (the carnivora) in the flesh and bones. "When 

 present in undue amount in a given quantity of urine they 

 tend to crystallize out, but when a large amount of phos- 

 phate of magnesia is present, it is only necessary that the 

 urine should be retained longer than usual in the bladder 

 and that decomposition should set in with evolution of am- 

 monia, to have the insoluble ammonia-magnesian phos- 

 phate at once thrown down. 



Sulphate of lime is derived from sulphates in the water 

 or the oxidation of sulphur contained in the albuminoid 

 principles of food. 



Urea, Uric Add, Hippuric Acid, Creatine, Creatinine, 

 Kiestine, Leuoin, Tyrosin, etc., are all nitrogenous elements, 

 derived from the waste of muscle and gelatinous tissues, 

 or from albuminoid matters in the food. Urea is to be 

 looked on as the healthy product of such decomposition, 

 while uric and hippuric acids, etc., are products in which 

 the process of oxidation has stopped short, leaving the 

 products in a less soluble condition and more Hable to 

 crystalHze out of the urine. Impaired breathing from dis- 

 eased lungs or otherwise and imperfect action of the hver, 

 whether from local disease in that organ or from feverish 

 states, with impaired functions generally, are therefore 

 among the causes which strongly predispose to urinary 

 calculi. 



Beside these a certain amount of mucus, fat, coloring 

 matter and even hhod enter into the formation of urinary 

 calculi. 



Accessary Causes. To the above named causes favoring 



