AND ITS RELATION TO ANIMAL LIFE 121 



rain in South Australia, only about nine inches 

 per year, and the average yield of wheat is 

 only about eight bushels per acre so the 

 straw never has an excessive load to carry, 

 consequently there is no ulterior cause why 

 the crop should become laid. Thus, the straw 

 must be weak in itself. 



Another point which confirms this theory is 

 that in every case (excepting one experiment) 

 an application of salt decreases the rust in pro- 

 portion to the increasing quantity used, so 

 that in the case of a heavy dose the rust is 

 nearly banished, and the only value I have 

 ever heard attributed to salt in connexion 

 with a grain crop was that it strengthens the 

 straw by helping to dissolve silica, of which 

 the straw is largely composed, and which has 

 been proved by analysis to be deficient in 

 sugar cane attacked by this disease. 



One professor at the Rust Conference said 



" that although he had been in Japan for eight 

 months as adviser to the Government, he did 

 not now remember ever having heard of rust 

 there, although theoretically Japan furnishes 

 conditions almost exactly suited to the de- 



