1 88 TUBERCULOSIS 



many of the symptoms described above may occur simultane- 

 ously. The symptoms of acute miliary tuberculosis, "gal- 

 loping consumption," are rapid loss of flesh, depression, poor 

 appetite, cough, weakness, rapid breathing, harsh respiratory 

 sounds, some elevation in temperature, increased pulse rate 

 and, sometimes, enlarged lymphatic glands. The course of 

 this form of tuberculosis is always rapid and terminates in 

 death. Acute miliary tuberculosis occurs when large num- 

 bers of tubercle bacteria are di.scharged into the blood or 

 lymph currents. They are then carried to other parts of the 

 body, filtered out in the capillaries of the lungs, liver, spleen, 

 kidneys and elsewhere, causing tubercular lesions in each of 

 these localities. The lesion from which the infectious material 

 entered the circulation may have been a comparatively small 

 nodule. This form of the disease is more likely to appear in 

 young animals than in adults, and is more common among 

 swine than in cattle. 



§ 143. Morbid anatomy. The usual direct anatomical 

 changes following the invasion of tubercle bacteria are the for- 

 mation of nodules or tubercles. A tubercle has been defined 

 as, "a small nonvascular nodule composed of cells varying in 

 form and size with some basement substance between them 

 and with an inherent tendency to undergo central necrosis." 

 In a large number of cases the individual tubercles are dis- 

 tinct and easily recognizable, while in others they are coal- 

 esced, forming a mass of necrotic tissue. The lesions vary, 

 therefore, from well isolated minute or larger nodules to 

 masses or cavities containing a purulent, caseous, or calcified 

 substance. 



The location of the primary lesion depends upon the 

 channel of infection. If the specific organisms are lodged in 

 the oral cavity or pharynx they may, through an accidental 

 abrasion of the mucosa, be taken to some of the lymphatic 

 glands about the head; if they are taken directly through the 

 respiratory passages into the lungs they either develop no- 

 dules in the lung tissue proper, or they are carried through 



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