t *88 J 
If mlafmata exercifed their deleterious 
power upon the blood, as was in former 
times generally believed, and Hill is by a 
few, nothing would be more common 
than relapfes. 
The blood is only a condu&or of the 
miafmata, and thefe only ad when they 
find a favourable difpofition in the indivi¬ 
dual j and as in every individual the dif¬ 
pofition is not the fame, fo all perfons are 
not equally fubjed to feel its influence. 
Joab, a Jew, who pradifes as a phyfician 
at Smyrna, has never been attacked with 
the plague, although for many years he has 
treated people in that diforder. 
It is for the fame reafon that fome epi¬ 
demics only attack perfons of certain 
temperaments, or certain fpecies of ani¬ 
mals. 
Hippocrates mentions a difeafe which 
attacked only the bond-men and maid- 
fervants, and fpared entirely the nobles 
and 
/ 
