222 DISEASES OF THE PARENCHYMA OF THE LUNG. 



Under this category those cases may also be included in which the 

 cheesy inflammatory products of the results of tuberculosis of the 

 genito-urinary apparatus, the intestines, mesenteric glands, joints, 

 bones, or superficial lymphatics, are followed by tubercular disease. 



In cases of doubt the discovery of cheesy residua in these organs 

 may decide the question in favor of tuberculosis. It is quite possible 

 that in the future, the danger of pulmonary tubercle, which the pres- 

 ence of the cheesy residua of enlarged lymphatic glands produces, will 

 rank among the indications for the extirpation of peripheral lymphatic 

 tumors, and even for the performance of resections and of amputations. 



With regard to the frequency of consumption, it is supposed that 

 from a seventh to a fifth of all deaths are the result of this disease, 

 and that in nearly the half of all cadavers we find traces of the nutri- 

 tive disorders from which pulmonary consumption proceeds. 



During foetal life and early childhood, consumption is rare. Even 

 in later childhood, bronchial catarrh, with swelling and cheesy meta- 

 morphosis of the glands, or " consumption of the bowels," is far more 

 common than pulmonary phthisis. 



Toward the period of puberty, and still more so between the twen- 

 tieth and thirtieth years, the malady attains its greatest frequence, be- 

 coming rarer as life advances, without becoming quite unknown even 

 in extreme old age. Males and females seem to be equally liable. 



The former belief in the prevalence of the disease in cold climates, 

 and its comparative rarity in warm ones, is not borne out ; regions 

 situated far to the north being wellnigh free from it. Hirsch declares 

 that the mean temperature due to the geographical and territorial 

 situation of a place has absolutely no influence upon the production or 

 frequence of consumption ; that great alternations of temperature and 

 a high degree of moisture favor its development, while in elevated re- 

 gions its appearance is rare. The rarity of consumption in malarious 

 regions is not constant, and is scarcely due to the influence of the ma- 

 laria, but it depends rather upon other causes, such as the paucity of 

 the population and lack of culture in many regions afflicted by malaria. 



Persons with heart-disease enjoy a certain immunity from consump- 

 tion. Probably this does not depend upon the more venous quality 

 of their blood, but is rather because the products of the pneumonias, 

 from which they suffer with comparative frequence, have but little 

 tendency to cheesy degeneration, owing to the moist and engorged 

 state of their lungs. Emphysernatous persons are seldom consump- 

 tive, but for a different reason : their dry, bloodless lungs rarely in- 

 flame ; but, once attacked, the danger of degeneration is great. 



ANATOMICAL APPEARANCES -A great variety of lesions are found 

 in the lungs, especially pathological cavities, extensive infiltration and 



