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A series of experiments on the optimal temperature of germi- 

 nating spores has been instituted. A few species only have been 

 taken up, but thus far fungi which thrive best in a cold, wet 

 season are found to prefer a low germinating temperature (See 

 experiments on the Clover Rust, Bull., XXIV, pp. 135-138). 

 Those thriving in a hot summer show a corresponding high opti- 

 mal temperature. 



It is not difficult to see that definite information on the limits 

 of germination of the spores of each of our troublesome fungus 

 parasites, might be of great service to owners of green-houses and 

 forcing-houses. The preservation of a specific temperature, not 

 injurious to the host plant, might deprive the fungus in certain 

 cases of its power of attack. 



It is apparent that many plant diseases have their basis in some 

 physiological derangement in the plant itself ; and that a better 

 knowledge of the conditions of the health and hygiene of various 

 forms of green-house plants is quite as essential as a knowledge 

 of the particular mineral poison which will destroy the parasite 

 likely to appear after the host has fallen into ill-health. These 

 questions of environment will no doubt be eagerly taken up by 

 the vegetable physiologists of America, who find few subjects 

 worthy of their powers and their training and are forced thereby 

 into other fields of exertion. 



W. R. Dudley. 



