Fttnislfir Fio);// iif fllliio/s. 1 t7 



iimcli ;itt(Miti()n h;is l^poii <i'iv(Mi t(t coiitafi^ioiis discuses of ani- 

 nials. Tin- iin))()rtance of scientific iiiVHsti<>ati()iis in this latter 

 direction ( aiiiiot be overestiniatetl, vet it woiiM not he difticult 

 to show that every argument in support of these is applicable 

 also to encourao-enient upon the study of the diseases of plants. 

 In fact, it has now come to be ^^enerally admitted that these 

 very maladies of animals are directly due to various s])ecies of 

 the same classes of low ve^^etable organisms which afflict, as 

 parasites, the valuable plants and crops. Tn some instances the 

 very same s])ecies of fungi prey n))oii jihiiits oi- j)lant-products 

 and living aninuils. The coniinon moulds aiv fungous growths, 

 and mouldy grains and other articles of vegeta1)|e foods are 

 commonly believed to l)e injurious to man and animals. Some 

 contagious diseases of man have been ])i-oved to l)e due to or- 

 ganisms normally living on vegetable substances, and there is 

 much reason to su|)pose that all the pathogenic bacteria, and 

 their allies, are or were ])rimarily simply deconi))osing agents of 

 dead substances. <'ertainly the nature of the contagious dis- 

 eases of animals cannot be fully known without the closest 

 investigations of the life of the disease organisms outside of the 

 animal body. The studies of fermentations and jjutrefactions 

 have already lead to most important results in pathologv, and 

 it is confidently believed that there is much more to be gained 

 in the same way for the advancement of knowledge in regard 

 to disease and injury, not of animals only, but of plants as 

 well: while a projjcr study of the diseases of ])lants must help 

 to a better understanding of the serious nnilailies of man and 

 the domestic animals. 



The nomenclature adopted in this pajiei- has hecn the re- 

 sult of considerable incpiiry ami an earnest endeavor to con- 

 form to the latest opinions of the I)est authorities, as well as to 

 most nearly fulfill the requisites of this branch of science. 

 Unfortunately, in numerous cases there are many synonyms, 

 and as names were given to species before any natural classifi- 

 cation could possibly be made, and as the life history was in the 

 earlier times usually unknown, different writers assigned the 

 same species to widely different ))Ositions in their systems of 

 arrangement. The descriptions ])y the older authors are mostlv 

 meager, and entirely devoid of accurate microscopic cliaracter- 



