QUESTIONS AND ANSWERS 125 



Mention the conditions that favor the growth of wool or of improve- 

 ment in its quahty. 

 Good feeding of a rather high nitrogenous diet; neither too hot 

 nor too cold temperature; dry surroundings. Salt and sulphur 

 are thought to aid the growth of wool ; at any rate, the former is 

 indispensable as a part of the diet and should be given regularly ; 

 the latter is valuable as a mild laxative and, by its general tonic 

 action, may improve the fleece. 



What precautions may be taken to limit the growth of an injuriously 

 long, thick coat of hair? 



Warm quarters and blanketing will cause shedding. Clipping 

 may be resorted to. 



Ueine 



Give in full the functions of the kidneys. 



They are the filtering organs of the body. They excrete urine, 

 which consists of nitrogenous waste products, salts and other ex- 

 crementitious substances. 



What is the structure of the capsule of the kidney and how does this 

 capsule affect the progress of the urine through the urinif- 

 erous tubules, pelvis and ureter? 

 It is composed largely of fibrous tissue and is rigid and unyield- 

 ing. The internal pressure, therefore, tends to force the urine 

 through the various canals. 



Describe the cortical layer of the kidney and state where the secretion 

 of the liquid and solid elements of the urine takes place. 

 The cortical layer is the essential secreting region. It contains 

 the Malpighian bodies and convoluted tubules, as well as the be- 

 ginning of the straight collecting tubules. Beneath the capsule, 

 also between the cortex and medulla, is a narrow layer in which 

 no glomeruli are found, otherwise the cortex is filled with them. 



In the glomeruli, the water and perhaps the salts are passed 

 out, while in the tubules the organic matter is excreted. 



Give the composition of urine. 



Water. 



Organic matter: Urea, uric acid, hippuric acid, creatine, crea- 

 tinine, benzoic acid, ethereal sulphates of phenol and cresol, color- 

 ing matter and mucus. 



Salts: Sulphates, phosphates and chlorides of sodium, potas- 

 sium, calcium and magnesium. 



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