EXTRACT XXXV. 



ON TUBERCULOSIS. 



THE term tuberculosis is here chosen in preference to the 

 terms consumption, phthisis, or tabes, as having a generic 

 signification and adaptability which the latter terms do not 

 possess. 



Tuberculosis, as a generic term, includes a very large 

 array of specific varieties of the disease, each of which is 

 due to the growth of a, or the, specific bacillus tuberculosis 

 a near relation of the bacillus lepr<e in a structural 

 medium, capable of determining its particular manner of 

 growth and pathological development, and the evolution 

 of the particular form of the disease. Thus, according to 

 the incidence of its etiological factors, it attacks the pul- 

 monary tissues, the parenchyma of particular organs, the 

 free surfaces of lining membranes, and the textures of the 

 skin, manifesting in each instance its specific characteristics 

 modified by the medium in which it is developed, and the 

 textural nature of its environment. This classification is 

 now rendered possible and necessary by the discovery that 

 they are each and all due to the growth and influence of 

 a common microbic organism, and that they are each and 

 all dependent for their individual and distinguishing 

 character on the operation of local modifying influences 

 and factors on their common pathological evolution from 

 one variety of microbic organism. 



Being thus evolved from the growth of a common 

 pathogenic micro-organism, it must follow that the organ- 

 ism must obtain access to, and become supported by, some 

 available nutritive material possessed in common by the 



