DISEASES OF THE URINARY ORGANS. 159 



the liver, lungs, or other distant organ resulting in the escape of albu- 

 men in the urine; disorders of the liver or of the blood-forming func- 

 tions resulting in hrematuria or haeinoglobinuria ; sprains or other in- 

 juries to the back, or disease of the spinal marrow which cause the 

 escape of blood with the urine; the presence in the bladder of a bac- 

 terian ferment which determines the decomposition of the mucus and 

 urea, the evolution of ammonia and the consequent destruction of the 

 protecting cellular (epithelial) lining of the bladder; or the irritation 

 caused by the presence of an already formed calculus may produce the 

 colloid or uncrystallizable body that proves so effective in the precipi- 

 tation of stone or graveL It has long been known that calculi will 

 almost infallibly form around any foreign body introduced into the 

 kidney or bladder, and I have seen a large calculous mass surrounding 

 a splinter of an arrow that had penetrated and broken off in the body 

 of a deer. The explanation is now satisfactory the foreign body 

 carries in with it bacteria which act as ferments upon the urine and 

 mucus in addition to the mechanical injury caused by its presence. 

 If such a body has been introduced through the solid tissues there is 

 in addition the presence of the blood and lymph derived from the 

 wounded structures. 



CLASSIFICATION OF URINARY CALCULI. 



Urinary calculi arc most conveniently divided according to the local- 

 ity in which they are found. Thus we find first renal calculi, formed 

 in the kidney (Plato xi, Fig. 1), and which for cattle must be again 

 divided into calculi of the uriniferous tubes, and calculi of the pelrix. 

 The second class are named uretral calculi, because they are found in 

 the duct leading from the kidney to the bladder (ureter). The tliird 

 class are the vesical calculi, from the bladder or vesicle in which they 

 are found. The fourth class are the urethral calculi, and arc found in 

 the duct leading outward from the bladder through the penis (urethra). 

 The fifth and last class are the preputial calculi, since they are found 

 within the sheath of the penis (prepuce). 



Calculi may also be classed according to their chemical composition, 

 and this has the advantage of suggesting the special cause of each as 

 found in the food, water, soil, or general condition of health. This 

 classification affords no guide to their location nor symptoms, as calculi 

 of the same chemical composition may be found at any part of the uri- 

 nary passages, as those formed in the kidney may pass on through all 

 the various passages outward, unless it is found at any point of their 

 progress that they have grown so largo that the passage will not admit 

 them. The following are among the concretions found in the various 

 parts : 



(1) Coralline calculi. These are of a dull white color and irregular 

 surface, like coral. They are made up of hard and resistant layers 

 evenly deposited around a central nucleus. (Plate xi, Fig. .'*.) Their 



