Epidemics. 203 



primitive species, and so continues for its natural period, 

 as the Black death returning to simple Levant plague, or 

 the disease has but a limited duration, and, by the reproduc- 

 tive power in hybridity being weaker than in the pure, ex- 

 tinction follows as a sequence and a check to vigorous re- 

 production.* 



Upon what grounds, it will be asked, is a chronic affec- 

 tion made to ally itself to an acute disease, and to run a 

 course of such fearful haste as to do more in one month 

 than in its pure form it does in ten, twenty, or more years ? 

 Its chronic spongy gums, and its chronic bowel affection, 

 and its exceedingly chronic sphacelus, are so many adverse 

 conditions to an acute disease. Perhaps one answer to this 

 is, How does inflammation at one time assume a chronic 

 form and at another an acute form, one lasting years and 

 the other only a few days ? But it must be borne in mind 

 that, directly as is the intensity of an epidemic, so is its 

 acuteness, and as a rule so is its infectious nature intensified ; 

 and when supplemented by an acute rubeoloid disease, first 

 showing itself not far distant from the original seats of both 

 diseases Ethiopia, which on one side has the Nile running 

 through its territory, and, on the other, is nigh to the con- 

 fines of Arabia. It is not difficult, under such circumstances, 

 to conceive that the endemic peculiarities of each, when 

 quickened and intensified by an epidemic era, favourable 

 for the regeneration of both endemics, should, by its 

 adaptency for each, make the nutritive focus of each assimi- 



* In speaking of hybridity in such germs as are here called zooitic 

 fungi, or active animal germ sarcode, the condition of sexes is not 

 necessarily implied, but that germs have new properties and increased 

 powers of propagation by one kind of germ feeding upon an allied 

 animal germ, whereby activity, both as an infectious agent and as a 

 poison, may be increased and stimulated so as to modify and change 

 the kind of disease produced ; just as larvae in a hive are affected by the 

 kind of food supplied, so that an ordinary larva is changed into a queen 

 bee when perfect, and so becomes a reproductive bee. Culture also 

 greatly affects the functions and nutritive properties of vegetables. 



