THE MODERN ERA 



The doctrine of the autogenetic origin of disease in 

 plants reached its high-water mark in the philosophy of 

 Franz Unger, as we have already seen. The end of the 

 eighteenth and the early days of the nineteenth century 

 saw a growing school of mycologists whose observations 

 and studies convinced them that the spore-like structures 

 of the entophytic fungi were, in reality, reproductive 

 bodies; that they germinate and hence must serve to 

 propagate their kind; and finally that these entophytes 

 must be independent organisms causing the diseased 

 conditions with which they are constantly found associ- 

 ated and not the result thereof. To this school belonged 

 such noted mycologists as BulUard, DeCandolle, Link, 

 Tulasne, Leveille, and others (de Bary, 1853 : 107). 

 Positive proof in the form of carefully checked infection 

 experiments were, however, largely wanting 



The brilliant and classic studies of the Tulasne' 

 brothers on the life history of such parasitic fungi as 

 Claviceps, the Erysiphaceas, the Uredinales, and the 

 Ustilaginales had unfolded the fact of polymorphism in 



' Tulasne, L. R. et Ch. : Mfimoire sur les Ustilaginecs comparees 

 aux Uredinfes, Ann. Sci. Nat., 3:7: 12-127, 1847; and the following 

 by L. R. Tulasne alone: Memoire sur I'Ergot des Glumacees, Ann. 

 Sci. Nat., 3 : 20 : 5-56, 1853; Second Memoire sur les Uredinees et les 

 Ustilaginees, Ann. Sci. Nat., 4:2: 75-196, 1854; and finally that extra- 

 ordinary work by the Tulasne brothers, Selecta fungorum carpologia, ea 

 documenta et icones potissimum exhibens quae viria fructuum et 

 seminum genera in eodem fungo siraul aut vicissim adesse deihonstrent, 

 1 :I-XXVIII + 1-242, 1861; 2 :I-XIX + 1-319, 1863. 



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