PRAIRIE FARMER'S POULTRY BOOK 



which contain blood vessels through the walls of which oxygen is taken 

 up. Air spaces also occur in the feathers, bones, and elsewhere, making 

 the bird's body light and buoyant. 



A knowledge of the respiratory system is important on 

 account of its bearing upon the hygienic care of the flock 

 and a comprehension of the diseases which attack its organs. 

 The more common diseases of the respiratory system are : 

 Catarrh, roup, diptheria, gapes, pharyngitis, bronchitis, asper- 

 gillosis, inflammation of lungs and, occasionally, tuberculosis. 



Circulatory System 



There are two systems of circulation, the blood vessels and 

 the lymphatics. 



Blood circulation. The blood is the red fluid which is the 

 carrier of the food elements to the cells and tissues of the body 

 for their repair and upbuilding and of the waste matter to the 

 lungs and kidneys to be eliminated. About 90 per cent of the 

 blood is water; the remaining portion comprises the corpuscles 

 and the plasma. 



The corpuscles are red and white. The red corpuscles in a 

 fowl are nucleated, elliptical discs ; in human blood they are 

 circular discs, non-nucleated, and smaller. The color of the 

 red corpuscle is due to the hjemoglobin, containing iron and 

 manganese. The affinity of the haemoglobin for oxygen re- 

 sults in oxyhEemoglobin, and this becomes the carrier of 

 oxygen from the lungs to the cells of the body. The white 

 corpuscles are nucleated and consist of living protoplasm, 

 exhibiting amoeboid movements. They perform important 

 functions, destroying disease germs, healing wounds and 

 building up tissues. 



The organs of circulation are the heart, arteries, capillaries 

 and veins. The contraction of the heart forces the arterial, 

 bright red blood coming from the lungs through the arteries 

 to the capillaries, and the veins collect the venous, dark red 

 blood from the capillaries and convey it back to the heart, 

 whence it is forced to the lungs to be again charged with 

 oxygen and returned to the heart for another journey. The 

 heart is a muscular organ with four cavities — two auricles and 

 two ventricles. The pulsation of the heart is more rapid than 

 in other animals, hence oxidation in the lungs and capillaries 

 is undoubtedly more rapid and the blood is, therefore, hotter. 



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