1904] SMITH—PUCCINIA ASPARAGI 43 
INDIRECT RELATION. 
By this is meant the effect of moisture acting upon the parasite 
through its effect upon the host, and limited therefore to soil moisture. 
It has been attempted to show in this respect: 
That under any but very unusual conditions of atmospheric 
moisture the indirect relation is of greatest importance. 
That an abundance of soil moisture during the summer has a 
marked effect in retarding the development of this fungus by giving 
the host greater vitality and resistance. 
That this is shown by the effects of the varying summer rainfall 
in different seasons, by the differences in the water-retaining capacity 
of different soils, and by the effects of irrigation. 
UNIVERSITY OF CALIFORNIA, 
Berkeley. Calif. 
