228 PRINCIPLES OF VETERINARY SCIENCE 



disease if they had not been put to work too soon, have suc- 

 cumbed during the convalescent period. 



Disease may terminate in one of the three following ways: 



(1) Complete recovery occurs if the natural, defensive, and 

 reparative powers of the body are capable of neutralizing the 

 poisons, eliminating debris, and repairing the tissues. Com- 

 plete recovery from disease is known as resolution. It may occur 

 early in the attack or not until very late. 



(2) Incomplete recovery follows after a disease has run its 

 course and left some permanent impairment of tissue (sequelae 

 of disease); for example, adhesion of the lungs after pleurisy; 

 opacity of the previously transparent part of the eye; deformities 

 of bones. Many times the organ will be, for all practical intents 

 and purposes, as serviceable as before. 



(3) Death occurs when the vital organs suspend their functions. 

 It is brought about by the failure of either the respiratory, the 

 circulatory, or the nervous functions, or it may be due to a com- 

 plication of these causes. In the case of many infectious diseases, 

 in which the organisms gain entrance to the blood stream, death 

 is due to a combination of physical and chemical effects. For 

 example, the bacteria may clump together and stop the flow of 

 blood in certain capillaries; the bacterial toxins may poison the 

 tissues to a point where they are rendered inactive; the leuko- 

 cytes may become paralyzed; the antibodies may become ex- 

 hausted. Death may occur suddenly, in which case the animal 

 collapses, becomes unconscious, and for a few moments at most 

 is thrown into convulsions, as in lightning-stroke or sunstroke. 

 In the majority of cases death comes on gradually, and terminates 

 in the so-called death agony or death struggle. This mode 

 shows progressive paralysis of the different systems of body 

 organs. Animals in the agonal state are unable to rise, lie flat 

 on one side, and lift the head from time to time and let it fall 

 heavily. They may sweat profusely and involuntarily void 

 urine and feces. 



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