320 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



vigour that it kills them almost immediately, and itself thus becomes a 

 victim to starvation. 



The writer maintains his position as to the mycoplasm theory and 

 states that pure cultures give no evidence that lends support to that 

 hypothesis ; he further believes that the entering germ tube and sub- 

 stomatal vesicle would be discovered if serial sections were cut through the 

 patches at the margin of which " protomycelium " and " mycoplasm " are 

 found. He believes the mycoplasm theory has arisen through reading the 

 phenomena backwards. (See also abstract under Uredinea.) 



As to bridging species, the author states that he is convinced that it 

 is here we have a clue to the phenomenon of the ever-widening cycle of 

 adaptation. In 999 times out of 1,000 the spores adapted to a small 

 given circle of host-plants cannot successfully break through the defences 

 of another circle. Bat in the 1,000th case a spore may infect an alien 

 host, and once established its progeny can go on infecting that new host. 

 The evidence compels us to believe that the host reacts upon and affects 

 the physiological powers of the fungus ; the effects are invisible and 

 produce no distinguishable morphological impression on the spores. But 

 if very slight morphological results should follow, we have then the clue 

 to the graduation of morphological differences, sufficiently distinct for the 

 determination of species. — A. D. G. 



Fungous Diseases, Farmers' Bulletins (U.S.A. Dep. Agr. 219, 

 221, 231, 243, 250). -The following are part of a series of bulletins 

 issued by the United States Department for the use of farmers and 

 cultivators. 



219. Lessons from the Grain Rust Epidemic of 1904, by Mark Alfred 

 Carleton, with six woodcuts. 



221. Fungous Diseases of the Cranberry, by G. L. Shear, with eleven 

 woodcuts. 



231. Spraying for Cucumber and Melon Diseases, by W. A. Orton, 

 with eight woodcuts. 



243. Fungicides, and their Use in Preventing Diseases of Fruits, by 

 M. B. Waite, with seventeen woodcuts. 



250. The Prevention of Stinking Smut of Wheat, and Loose Smut of 

 Oats, by Walter T. Swingle, with seven woodcuts. 



These bulletins are simply popular expositions for the use of those 

 interested in the cultivation of the various plants, and are not expected to 

 contain any new facts or experiments, or novel information calling for 

 special notice. They may be suggestive to the Agricultural Departments 

 of other Governments as to the methods which may be employed for the 

 diffusion of useful knowledge where it is often much needed. — M. C. G. 



Fungous Diseases, Report for 1904. By G. P. Clinton, Sc.D. 

 (U.S.A. Exp. Stn. Connecticut', with 37 plates). — This report deals 

 with about thirty-three separate diseases on various plants, including 

 Asparagus Rust, Smutty Mould of Fig, Bacterial Disease of Mulberry, 

 Stem Rot of Onion, Rhizoctonia or Rosette of Potato, Root Rot of 

 Radishes, and Stem Rot of Rhubarb ; followed by a Report on Downy 

 Mildew or Blight of Musk Melons and Cuqumbers (Peronoplasmopara 



