1 2 M UMFORD, Physique of Manchester Graiin/iar School Boys. 



In conclusion, in assii^ning the value to each of the 

 factors, I am inclined to the opinion that the diminution 

 of incidence of early infectious disease during the first 

 period of childhood {i.e., before the age of seven years) is 

 one of the most potent factors which has produced the 

 improvement that we have noticed. 



