2Q State Horticultural Society. 



lowing- proofs, that this microbe ( Bacillus -amylovorus) .causes the dis- 

 ■ease; "(i) The microbes are found in immense numbers in freshly 

 blighted twigs; (2) they can be taken from an aft'ected tree and culti- 

 vated in pure cultures (and in this way can be kept for months at a 

 time) ; (3) by inoculating a suitable healthful tree with these cultures 

 the disease* is produced; (4) in a tree so inoculated the microbes are 

 again found in abundance." Mr. Waite further established by his re- 

 searches that the microbe does not survive the winter in the soil as was 

 once guessed, but rather in its native medium and habitat, the inner bark 

 and cambium layer of the twig stems, where, under conditions of heat 

 and excess -of moisture in the early spring, they begin to multiply. 

 Their activity, combined with other causes stimulates an excess of ex- 

 uding gum in which they thrive. This gum, being visited by insects 

 which also frequent flowers, becomes the source of inoculation for the 

 flowers, and the flower nectar affords the best possible culture medium 

 from which they spread again into the inner bark and cambium of the 

 young, juicy twig stems. In' this way the entire orchard may become 

 infested in a few days. Fortunately, the period of excessive activity of 

 this microbe is short, so that in late summer and through the winter its 

 life is barely maintained, and at these periods man may attack the 

 enemy. Generally there are a few living, but inactive, germs during 

 these seasons, to be found a few inches toward the trunk from the black- 

 ened portion of the twig, and if the twigs are all pruned a sufficient 

 distance from the blighted portion, and burned, the future spread of the 

 ■disease may be checked or absolutely prevented. 



In this way if the practical horticulturist will supplement the re- 

 searches of the practical biologist with his intelligent study and per- 

 sistent labor, he may some day possess the gleaming gold beyond the 

 imblighted blossoms, and the biologist will come in for his taste of the 

 luscious pears and apples. 



No department of human knowledge can stand to itself alone. Blot 

 •out the world's knowledge of astronomy, and every map of the globe 

 •or any part of it, would vanish, and every traveler upon the land, and 

 •every steamship upon the seas would be lost in the bewilderment of 

 darkness. Obliterate the science of physics and chemistry, and every 

 mechanical invention, every precious metal and its thousands of useful 

 combinations, every wheel of commerce and every fabric of manufac- 

 ture would be resolved in to that elemental state of nature that could be 

 likened unto the "virgin forest" and defined as the place where "the 

 hand of man has never set foot." Shut out from the human mind all 

 knowledge of biology, horticulture and agriculture, and the human race 

 would lapse to the low level of primeval savagery, and stand upon the 



