Epidemics. 189 



motion for the annihilation of living beings, transient or per- 

 manent, of mediate or immediate effect. The most power- 

 ful of all was contagion ; for in the most distant countries, 

 which* had scarcely yet heard the echo of the first concussion, 

 the people fell a sacrifice to organic poison the untimely 

 offspring of vital energies thrown into violent commotion." 



Comparing the plague of Justinian of 526 A.D., which is 

 Gibbon's date for that plague, with the Black death of 1348, 

 it may be justly stated that both were bubonic and car- 

 buncular plagues, with a superadded lung disease in the 

 latter epidemic, which was as diagnostic in its laboured 

 breathing and spitting of blood as the presence of buboes, 

 etc., were in true Levant plague ; but carbuncles appear to 

 have been less prevalent in the latter epidemic than in the 

 Justinian one. 



The general conclusion arrived at by comparing these two 

 well-authenticated and carefully described epidemics is this, 

 that distinct and specific affections in themselves occasionally 

 unite to constitute one continuous disease, by which the 

 entire system is pervaded and brought under complete sway 

 and conquest ; and in this new form of infection and wide- 

 spread diffusion, at least for a season or considerable 

 duration of time, as of several years, can be induced and 

 sustained. 



A modification by blending appears to be the natural 

 result of coalescence ; hence in the majority of cases, even 

 where convalescence was established, carbuncles never 

 appeared, though buboes in the neck, armpits, and inguinal 

 regions were common. 



Having advanced the hypothesis of hybrid diseases, as 

 distinct from parallel diseases running their course, though 

 modifying one another in one and the same person at the 

 same time, it may be asked, Is there any trace of hybridity 

 in any other disease than the Black plague, which probably 

 was the blending of an infectious lung disease of a more or 



