DISEASES OF THE PARENCHYMA OF THE LUNG. 



reaches the system from without through the medium of the air or 

 of impure contact. In spite of the most zealous research, no fixed 

 opinion has yet been formed regarding the nature of this material. 

 To some it seems the ordinary product of putrefaction (sulphide of 

 ammonium and carbonate of ammonium) ; to others it is a ferment, 

 or an independent substance evolved from putrid matter (sepsiri). 

 Finally, it has been ascribed to the presence of animal or of vege- 

 table organisms, or to vibriones, and of late to a spore Microspo- 

 rum septicum (Klebs). Whatever its nature, however, its presence 

 induces that grave and generally fatal fever called septicaemia or 

 pyaemia, the most formidable sequel to a surgical operation. 



6. P. 167. 



Sometimes the disease is exceedingly prevalent within certain 

 narrow limits, perhaps in a particular street or in certain houses, 

 case following case in quick succession. Under such circumstances 

 there is a strong warrant for the supposition that the disorder may 

 have assumed an epidemic infectious form. Such a view might 

 also find support in the additional facts that the disease has prodro- 

 mal symptoms, that its course is grave and often fatal, that it tends 

 to attack both lungs, that there is a swelling of the spleen, and that 

 other inflammatory disorders are epidemic at the same time. (See 

 Dr. Herr*s description of such an epidemic at Wetzlar in 1872.) 



7. P. 168. 



According to several competent observers, adherents of Cohn- 

 heim, the escape of red and white blood-disks into the air-vesicles 

 is not the result of rupture of the capillaries, but of migration. 

 At this stage, owing to the tension upon the tissues exerted by the 

 exudation, the capillaries convey less blood than before, although 

 the circulation is never quite arrested during life. 



8. P. 170. 



Formerly cheesy degeneration, or, as it used to be called, tuber- 

 culization, was regarded as a common consequence of croupous 

 pneumonia. Latterly, however, Buhl has stoutly disputed the idea 

 that croupous pneumonia is ever the precursor of a caseous degen- 

 eration, which latter he regards as the forerunner of a parenchym- 

 atous pneumonia. If, then, after a diagnosis of croupous pneumo- 

 nia, we find caseous degeneration post mortem (according to BuhT), 

 we must not infer that the former process has turned into the lat- 

 ter, but that our diagnosis was wrong. 



