Change of hicidence of Small-Pox. 1 1 1 



constant, and somewhat less than 2, up to the age of 45. 

 From 45-65 the discrepancy seems to be diminishing. The 

 unsteadiness of the numbers between 65-75 is probably 

 owing to the small number of actual deaths at those ages. 

 The cause of this difference is not easily seen, but the effect 

 appears very markedly at the age of 20 years, and continues 

 fairly constant in later life. 



Concluding this paper, which is merely descriptive, I 

 may sum up the results to be — 



1. That during the last 39 years, from some causes, 

 the death rate of children from small-pox has been greatly 

 diminished, the rate of diminution decreasing with age. (I.) 



2. That above the age of 35 this diminution is actually 

 changed into an increase of the death rate, in spite of the 

 decreased death rate at all ages. (I.) 



- 3. That, considering the death rate at all ages in com- 

 parison with the general death rate, the diminution in the 

 proportionate rate does not continue beyond the tenth year 

 and above 20 years the proportionate death rate increases 

 much more rapidly than the infantile rate decreases. (III.) 



4. That during the severe epidemic of 187 1-2, the pro- 

 portionate death rate at higher ages was not far from normal, 

 but that between the ages of 4 and 10 It rose to about ^^ 

 more than the normal proportion, while among children under 

 4 the proportionate rate was considerably diminished. (III.) 



5. That the incidence of small-pox on the two sexes 

 seems to be identical up to the age of 20 years, and that 

 after that age the death rate for males is about double that 

 for females. (IV.) 



