Each of the above theories was sustained by various writers, and 

 it may be of interest to note that Henry Ward Beecher was an 

 advocate of the theory that the cause of blight was due to the 

 autumn freezing of unripe wood. 



A. .T. Downing, the distinguished author of " Fruits and Fruit 

 Trees of America," applied the name " Frozen-sap blight " to the 

 disease. His theory was that the disease was due to the freezing and 

 thawing of sap. The sap thus lost its vitality, became dark and dis- 

 colored and poisonous to the plant. 



Thomas Meehan, editor of the " Gardeners' Monthly," supported 

 the idea that fungi were the cause of the disease; but no tests were 

 applied to prove that the inoculation of these fungi into healthy trees 

 would cause the disease. It was not until the year 1878, when W. T. 

 Burrill, Professor of Botany in the University of Illinois, announced 

 to the Horticultural Society of that State the discovery of bacteria, 

 apparently connected with the disease. Burrill also proved that the 

 disease was infectious, and could be communicated to healthy limbs 

 by inoculation, using the gummy exudation from an affected tree as a 

 virus. Not only was he able to produce the disease in pears, but also 

 in apples and quinces. Dr. J. C. Arthur, Botanist of the New York 

 Experimental Station, subsequently confirmed Prof. Burrill's results, 

 and thoroughly established the fact that a certain species of micro- 

 organism, named by the discoverer Bacterium amylovoruvi or the 

 starch destroying bacterium, was the sole cause of the disease. 



GeograpJiical Distribution. This disease is peculiar to North 

 America. So far it has never been recognized in Europe. Professor 

 Budd, of Iowa, who is familiar with the disease as it occurs in North 

 America, has inspected the orchards of Europe and states that no 

 trace of fire blight of pear or apple trees can be seen in Europe. It is 

 also unknown in New Zealand and Australia. In North America, 

 the blight extends from New York to California and from the 

 northern counties of Ontario to Texa-;. 



])r. Beadle, in a sketch of the history of the disease in Ontario, 

 states that, " In the early days of fruit-growing in the Niagara district 

 we had no pear tree blight nor apple tree blight. With the advent of 

 what people termed grafted fruit there came, after a few years, ' blight' 

 on the pear tree." " By the year 1840 it had spread considerably." 

 N. J. Clinton, of Essex County ; S. Hunter, of Oxford ; E. D. Smith, of 

 Wentworth ; Stone and Wellington, of Welland ; R. Hamilton, of 

 Argenteuil, reported its presence in their respective counties about 35 



9—136 



