142 MICROBES AND HEALTH. 



that those engaged in such work are more liable to con- 

 sumption, and contract the disease much more fre- 

 quently than those engaged in out door life. 



Tuberculosis. 



There is another form of consumption called tuber- 

 culosis. In this form of disease the septic blood pro- 

 duces or results in the formation of a poorly organized 

 tissue in the form of little nodules or tubercles, hence 

 the name tuberculosis. 



The tubercles are small nodular masses about the 

 size of a millett seed (variable). Tubercles are formed 

 as follows : First, an irritant, this excites inflammation 

 and new growth. These new cells are sometimes called 

 embryonic tissue, or granulation tissue, from their 

 granular appearance. It is a form of connective al- 

 ready described. When surrounding a tubercle or dis- 

 eased spot in the lung it presents a firm resistant sur- 

 face, and in the majority of cases checks the spread of 

 the disease, and that is the reason so many recover 

 from consumption. 



Tubercles are produced by a low form of inflamma- 

 tion resulting from self-generated poisons in the sys- 

 tem, as described. The tubercles do not contain blood- 

 vessels; their lack of nourishment and failure to organ- 

 ize as healthy tissue leaves them without foundation. 

 They are built from septic blood; they have but little 

 vitality, and no duty in life, hence easily break down. 

 Many new cells die; many white corpuscles lodge at 

 these points loose their vitality and die. Blood vessels 

 always contain the elements of fibrin, and these ele- 



