Epidemics. 201 



as two distinct, but closely allied, or twin diseases. That 

 both affect the throat, and chest, and the eyes is certain, and 

 also the skin. But the manner and degree of affecting those 

 parts," in many points, are widely different ; yet in the mode 

 of termination, when fatal, very similar in some points. In 

 both recession of the eruption is most dangerous; and in both 

 the breathing is often the chief and most important indica- 

 tion of a serious or fatal termination. These twin diseases 

 appeared in Arabia almost, if not quite simultaneously ; both 

 were skin diseases in a very important respect, and both 

 were infectious, and as a rule going about, or were epidemic 

 at the same time. In short, the inference was drawn 

 that they had one common origin, and that their origin 

 was in an older and distinct disease, which in lapse of ages 

 had varied considerably; and finally, at a new epidemic 

 era, had resolved itself into two free and independent 

 diseases, now known as measles and small-pox. 



The livid reddish skin, with pimples and sores, indicates 

 that two forms of eruption ran parallel in the same cases 

 the pimples and the reddish skin ; and from the minuteness 

 of the observer it is scarcely admissible that in the short 

 space of seven days the fact of one being the forerunner of 

 the other, and only different in degrees of age, could have 

 escaped observation and careful discrimination ; but though 

 the disease presented two forms of eruption, yet the dis- 

 tinctive character of the disease was that it should have 

 this specific form of dissimilar sores, or spots, and. reddish 

 skin, and the very absence of it ought only to indicate some 

 modification of the disease in particular individuals, in whom 

 the admixture of kinds of spots or sores were not observable 

 when under the influence of the plague at that time. 



So much for the eruption ; but neither small-pox nor 

 measles after recovery are followed by mortification of the 

 fingers and toes, etc. Neither, as a rule, is small-pox in 



