NATURE AND CAUSATION. 493 



different, or rather we should say opposite light. With these, 

 the various phenomena observed in the course of any true or 

 sthenic pneumonia are regarded as in reality manifestations of 

 a morbid state of the nutrient material, the blood ; the pul- 

 monary tissue-changes being simply the mode through which 

 the vitiated fluid purifies or rectifies itself This latter ex- 

 Yjlanation of the phenomena has many facts to support it. 



In the one view, the pyrexia and other phenomenal occur- 

 rences are to be regarded as resulting from the inflammatory- 

 product changes occurring in the pulmonic structures, which 

 must ever be looked upon as the essence of the disease ; in 

 the other, all these general and local disturbances and changes, 

 not even excepting the inflammatory-product alterations in 

 the lung- structures, are viewed as the result of the primary 

 vitiation of the blood. In this latter view the pulmonic struc- 

 tures are looked upon as possessing a selective power for the 

 specific abnormal material existing in the blood, and which, by 

 its elimination at the lungs in the form of so-called inflam- 

 matory product, relieves the htemal vitiation, and restores the 

 disturbed equilibrium. In this manner it is proposed to 

 account for the defervescence of the pyrexia, and amelioration 

 of many of the constitutional symptoms and features of the 

 disease. In regarding it as essentially a local diseased action, 

 the causes of which are often occult, or in their mode of action 

 difficult of explanation, the inflammatory product, instead of 

 being regarded as a local abstraction from the hosmal circula- 

 tion, of a specific contaminating agent, is to be viewed in its 

 development in the same light as swelling and effusion in 

 common inflammatory action of such open structures as 

 ordinary areolar tissue ; and to be capable of explanation, 

 as regards its occurrence, on physical or mechanical principles, 

 rather than by reference to what are chemico- vital. 



Whichever idea may be embraced, or in future may prove 

 more worthy of support, there are certain facts connected with 

 the development of pneumonia of which we are tolerably 

 satisfied, and in respect of which we have sufficient evidence. 

 We know (1) that there is a period of well-marked pyrexia, 

 which in acute uncomplicated cases runs a determinate course, 

 terminating in or succeeded by (2) a period of less-marked 

 fever, during which lung-consohdation is begun, or at least 



