On Plant Pati/oioc.y and Ba( ti;rioi.oc.y in 



mented on the difficulties frequently encountered in distinguishing 

 betu'een fungi and bacteria as causes and not simply consequences 

 of diseases in the vegetable economy, notably diseases of the 

 peach, pear, and grape. Concerning pear blight, he said: "It is 

 well known that the profitable culture of some of our best fruits 

 is rendered very problematical on account of their liability to 

 fatal diseases. The pear blight is an example. Many apparently 

 conflicting opinions have been published from time to time in 

 regard to the cause of this malady, some attributing to it fungi, 

 and others to bacteria, but withal, no remedy is suggested by 

 microscopists so far as I am aware." Agricultural colleges, he 

 urged, could "do a noble work" by helping to determine the 

 causes and prescribing remedies for some of the perplexing mala- 

 dies: leaf blister of the peach; grape mildew for which as yet no 

 remedy was known except possibly to grow species resistant to the 

 ailment; and the w^hole fabric of blights, molds, rusts, smuts, and 

 other diseases of crops. 



Congress appropriated monies " for the investigation of the 

 fungous diseases of plants, such as mildew, smut, blight, grape-rot, 

 Sec, and for experiments necessary to determine suitable remedies 

 for those diseases." ^^ Accordingly, in 1886, a mycological section 

 was organized within the Division of Botany, and Scribner, placed 

 in control of the section on July 1st, began investigating " diseases 

 of fruit and fruit trees, grains, and other useful plants, caused by 

 fungi." ®- 



Bacterial diseases of plants were then scarcely known, and 

 viruses, as known today, were unheard of except in connection 

 with diseases of animals and man. Occasionally the word " virus " 

 appeared in the literature of plant diseases but its use was non- 

 specific and mainly as a synonym for poison. Burrill, for instance, 

 when writing on pear blight,^^ said: "The introduction of the 

 virus introduced the cause of the disease, and the potency of the 

 virus was quite positively due to the living bacteria." This was a 

 statement made in 1881 and he, during approximately a decade of 

 study in cryptogamic botany, had passed from a doubt whether 



gi 



92 



Rep't of the Cornm'er of Agric. for 1886: 80. 

 Rep't of the mycological section, idepi, 95. 



"^Bacteria as a cause of disease in plants, op. cit., 527-531; also, 10th Ann. 



Rep't III. Indus. Univ., op. cit., 62-84. 



