MICHIGAN STATE POMOLOOICAL SOCIETY. 473 



initted to Prof. Beal of the Agricultural College, for microscopic 

 examination, Prof. Beal having very kindly offered to make this 

 examination to search for the presence of any fungoid growth 

 wliich might assist to account for the disease. Both the fresh 

 material and the same after it had begun to decompose, were smb- 

 mitted to examination under the microscope. As a comparative 

 test, specimens of healthy structure were submitted to the same 

 examination. Prof. Beal detected three or four different kinds 

 of fungoid growth in the diseased structures, but as the same 

 forms of fungus were detected in the healthy structures after 

 decomposition had commenced, the results thus far obtained 

 are simply negative. Prof. Beal does not feel satisfied with 

 the results of this microscopic examination, but proposes fur- 

 ther investigation on this point. xVt his suggestion I budded 

 a healthy tree with diseased buds to propagate the disease, so 

 that an examination may be made from time to time during 

 the growing season. I have also saved the pits from diseased 

 peaches, for a similar purpose. 



The detection of fungus as an origin of disease, and sepa- 

 i-ation of it from other forms of fungus growth, are the more 

 difficult from the fact that many fungi are polymorphic, or 

 have two or more forms, and charge their forms according to 

 the nature of the substance on which they feed. Thus the 

 barberry rust and the wheat rust were once thought to belong 

 to different families; now' they are known to be the same. 



A writer in the Gardener's Monthly (quoted in that wide- 

 awake agricultural sheet, the Michigan Farmer), speaking of 

 recent discoveries in cryptogamic botany, says : '•' It was soon 

 ascertained that a fungus, which usually grows only on dead 

 matter, would change its form and then attack living struc- 

 tures, and again change, according as it fed on various parts of 

 the plant. Thus dead branches in the earth will foster the 

 early fungi: and these, striking through the earth, will attack 

 a living tree, changing its form to fasten on these roots ; and 

 then the fungoid matter will so adapt itself as to enter into 

 the Avholc circulation of the tree." 



