348 DISEASES OF THE URINARY APPARATUS. 



III. Specific gravity. The specific gravity of normal urine 

 in most of our domestic animals is 1040. It rises in sugar dia- 

 betes and in fever, and diminishes in polyuria, interstitial nephritis, 

 febrile crises, and diabetes insipidus. 



IV. Reaction. In a normal state the urine is alkaline in herb- 

 ivorous animals (carbonate of lime) ; it is acid in the carnivorous 

 (acid phosphates). 



The urine of herbivorous animals becomes acid (phosphated) : 



1. When the herbivorous animals become carnivorous (through 

 abstinence, alimentation with powdered meat, milk diet of the 

 newborn. 



2. In diseases of the digestive apparatus, mainly in intestinal 

 catarrh (see this affection). Fever does not at all influence the 

 reaction of the urine. 



The urine of carnivorous animals becomes alkaline : 



1. When the food is wholly composed of vegetable substances. 



2. Immediately after meals. 



3. Through prolonged administration of alkalines. 



4. In catarrh of the bladder (ammoniacal fermentation of the 

 urine). 



V. Microscopic examination. This enables us to recognize 

 the presence of red corpuscles and leucocytes, tube-casts, renal, and 

 vesical epithelia ; also crystals of abnormal forms, fat-drops, bac- 

 teria, etc. 



1. Hematuria. Hematuria, or true urinating of blood, must 

 be clearly separated from hemoglobinuria, an affection in which the 

 urine is colored red by the hemoglobin derived from the blood and 

 muscles. These two morbid states were for a long time con- 

 founded, and even until quite recently a deep obscurity hid the 

 nature of these affections of the horse, and of the ox, which had 

 the pathological symptom " passage of the urine (see Hemoglo- 

 binemia of the Ox). This confusion is so much more to be re- 

 gretted, inasmuch as the distinction between hematuria and hemo- 

 globinuria is rendered very easy by microscopic search for red 

 corpuscles. 



Hematuria, like albuminuria, does not constitute a pathological 

 entity, but only a symptom which is common to the very numerous 

 affections of the organs of the uropoietic system ; the diagnosis 

 " hematuria," therefore, does not not mean anything at all. Among 

 its causes we must mention : 



