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691. The Urethra, (Plate XVIIL, P. and Plate XXXVIII., A. 5.), 

 is a tube which, in the male acts as an excretory duct, for both the 

 urinary and generative systems, and is contained within the penis. 

 In the female, however, it has only one use, and that is for the passage 

 of urine. 



692. Urine.— This is a fluid which may be either acid or alkaline 

 in its re action, according to the class of animal from which it is 

 excreted. In herbivorous animals it is alkaline, and of a rather 

 muddy appearance. The horse excretes, on an average, about eight 

 to ten pints of urine per day, but the quantity and quality can be 

 greatly altered by various conditions. These are chiefly, variation in 

 food and work, housing, the drinking of large quantities of water, and 

 the action of certain drugs and medicinal agents such as nitre, resin, 

 turpentine, juniper, cantharides, and the various balsams. 



