(53) 



eflfects, likewise, may thus be observed, obliging the most skeptical to admit 

 the agency of the parasites in causing the malady to which attention is given. 



Probably Prevost first discovered the fact, that the spores of fungi 

 germinate. This was in the first decade of our century. Since then many 

 eminent naturalists have given abundant testimony as to the true parasitism 

 of species, and of their individuality as such. We may, without disparag- 

 ment to others, mention the names of Leville (4), Tulasne (5), Berkeley (6), 

 and M. Bary (7) as authorities, whose writings have conclusively 

 established the fact that these parasites do cause the maladies attrib- 

 uted to them. Robin (8) and Leidy (U) have published prominent treaties 

 on the vegetable parasites upon living animals. 



Observers in this field are now much more numerous than ever before 

 and, having the advantage of the former contributions, are gaining rapidly 

 in the kaowledge of kinds and of the injuries caused by these small but in 

 no wise insignificant organisms. Preventives and cures naturally follow 

 investigations of cause. They certainly cannot precede the latter except 

 by accident ; hence, if any one feels like asking " What use ? " let him 

 possess himself in patience ; — in the coming time, man wall assert his 

 dominion here as well as elsewhere over the natural world. Something has 

 already been done. The vine disease in Europe has been kept down by the 

 use of sulphur, as are the rose and verbena mildews in green-houses. Some- 

 times prevention is attained by removing promptly attacked parts, as in the 

 case of the peach-rot, and, as further detailed below, sometimes by destroy- 

 ing the spores of the fungus, as in the bunt of wheat. Cultivators now often 

 unconsciously scatter the germs and ignorantly provide ways and means for 

 their development. The march or migration of a parasite of this kind is 

 sometimes as well marked as that of an injurious species of insect. 



Purcinin malvdcearum, Monf., affecting cultivated hollyhocks, has been 

 traced from South America through the United States to England and thence 

 to the continent as certainly as the Colorado potato beetle has across our 

 territory. Timely, intelligent action in such cases might avert great disas- 

 ter. Had this fungus attacked the cotton plant, as it was feared it would, 

 what estimate could be placed upon the loss ! What money- value is de- 

 stroyed iuour own state hy rust {Ftu-cinid (/ramiin.'i, Pets.) on wheat, oats, etc.; 

 what discouraging losses by the multitudinous blights upon our cultivated 

 crops, many of which are known, and others supposed to be, caused by para- 

 sitic fungi I 



4. Amiales des Sc. Naturelles. 1839, etc.; and •'Mycologie," and "Uredines," 

 m Diet. d'Hist. Nat., par D'Orbigny. 



5. Annales des Sc. Naturelles, 3 ser., tome VII, 1847 ; 4 ser., tome II, 18r)4._ 



6. Introduction to Crj-ptogamic Botany, London, 1857, p. 261. Outlines of 

 British Fungology, London, 1860, p. 68. 



7. Ueber der Brandpilze, 1853. Morphologie und Physiologic der Pilze, 1866, 

 and many papers in Annales des Sciences Naturelles and elsewhere. 



8. Historie Naturelle des Vegetaux Parasites qui croissent sur rhomme et sur 

 les animaux vivants, par Charles Robin, Paris, 1853. 



9. A Flora and Fauna Within Living Animals, by Joseph Leidy, Smithsonian 

 Cont. to Knowl.. Vol. 5, 1853. 



