GILWES: CHEMOTROPIC REACTIONS IN RHIZOPUS 33 1 



4. It is probable that the distribution of a parasitic fungus in 

 its host is due not so much to positive chemotropic stimuH as to 

 the dominant negative chemotropism towards its own staHng 

 products. 



In conclusion, I would like to express my great indebtedness to 

 Professor V. H. Blackman, of the Imperial College of Science and 

 Technology, London, who made this work possible by his invalu- 

 able assistance and unstinted advice. 



