ii6 Bulletin 65. 



water may easily pass through the sentinel stomach to develop in 

 the intestines. 



h. Chemical Poisons in the Tuberculous Body, 



The soluble chemical poisons in meat and milk of consumptives 

 will be noticed later as a potent cause alike of susceptibility to 

 tuberculosis and of its more rapid progress when already in the 

 system. 



Lesions and Symptoms of Tuberculosis. 



Tuberculosis appears under two great types : the acute and the 

 chronic, the first of which may run a fatal course of four to six 

 weeks, while the second may last for many years. At the outset 

 in the acute form, and for a great length of time in the chronic, 

 the disease-process may be confined to one organ or to one region 

 of the body and therefore the symptoms may vary exceedingly 

 according to the particular organ attacked. In many chronic 

 cases, with the tubercles confined to one organ or locality (lym- 

 phatic glands, liver, spleen, pancreas, etc.) the victim may be in 

 good condition and no sign of disease may be recognized by the 

 owner or even the veterinarian. In acute cases on the other hand 

 and when the tubercles are generally diffused through the body, 

 there is usually fever, wasting and emaciation in addition to the 

 characteristic symptoms of disease in particular organs. 



The lesions being caused by the colonization and local multi- 

 plication of the bacillus they tend to assume a rounded or nodular 

 form, from which has been derived the name of tubercle. Such 

 nodules may, however, be absent, the diseased product, being a 

 diffuse infiltration and thickening of the affected part. The early 

 nodule may vary in size from a millet seed up to a pea or more. 

 It is at first red, congested and firm ; soon it maj^ become gray in 

 the center though still red outside. With the grayish discolor- 

 ation comes a gradually extending death of the mass (coagulation 

 necrosis)and disintegration into a more or less soft cheesy looking 

 material (caseation). In cattle and chickens this cheesy nodule 

 tends to remain firm and it may even become gritty through im- 

 pregnation with earthy salts (calcification). Exceptionally it 

 will soften into a semi-liquid whitish" debris, resembling an abcess, 

 and this excessive softening is the usual course of tubercle in 

 swine. In some cases however the tubercle does not break down 



