230 DISEASES OF IBE PARENCHYMA OF THE LUXG. 



in either process, an extra amount of carbonic acid is formed, and an 

 extra quantity of oxygen is consumed in the system. If we compare 

 the rate of breathing with the elevation of temperature and the fre- 

 quence of the pulse in phthisis, it will be seen that the want of air i* 

 partially relieved by the greater depth of the breaths drawn ; for the 

 steep curves which generally are used to mark the character of the very 

 considerable fluctuations of the morning and evening temperature 

 hardly ever correspond to similar abrupt curves representing the rate of 

 respiration. The evening acceleration of the latter seldom exceeds 

 above six or eight breaths a minute, and in many cases is not more 

 than three or four breaths. In some cases no acceleration at all can 

 be detected. 



Pain in the chest and shoulders is a symptom which is often absent 

 throughout the entire course of the disease. It more commonly accom- 

 panies the pneumonic form than the tuberculous form of the malady. 

 In cases where physical examination leaves us in doubt, whether we 

 have to do with tubercle or with small scattered pneumonic deposits, 

 pleuritic pains may be of service both in the diagnosis and prognosis, 

 especially when accompanied by sputa tinged with blood. 



Consumption is preceded, in a large number of cases, by a more or 

 less protracted period of cough and expectoration, depending upon the 

 precursory catarrh, which afterward leads to catarrhal pneumonia by 

 extension into the air-vesicles ; and, subsequently, to consumption of the 

 lungs by caseous degeneration and disintegration of the inflammatory 

 products. It is highly important to endeavor to ascertain of every 

 patient whether his pallor, fever, and emaciation, have been preceded 

 for some time by cough and profuse expectoration, or whether these 

 symptoms have all appeared simultaneously and before the expecto- 

 ration became copious. In the first case, formerly ascribed to a post- 

 ponement of the fever and emaciation until an advanced stage of the 

 tuberculosis (according to Louis, this is the case in four-fifths of all 

 cases, while in one-fifth only do the cough and fever begin together), 

 it is more probable, ceteris paribus, that the disease is of pneumonic 

 nature, while the lattor class of cases are probably of tuberculous 

 origin. 



The duration of the precursory catarrh varies. Distinct evidence 

 of propagation of the process into the alveoli and of incipient phthisis 

 is sometimes discernible as early as the second or third week. Most 

 of the instances in which consumption is an immediate consequence of 

 measles and of whooping-cough are of this kind, as well as those in 

 which tuberculosis develops under the disguise of a catarrhal fever or 

 influenza. Conversely, a catarrh may have existed for months and 

 years, growing worse in whiter and improving during the summer, and 



