TuE Microscope. 



325 



In July, 1886, 1 collected for microscopical examination some of 

 the diseased plants, and, upon using higher magnification than form- 

 erly, found numerous bacteria within the cells of the affected parts. 

 An assistant, Mr. Charles Woodworth, was then asked to make 

 special experiments and observations. The results were speedily 

 convincing that a specific micro-organism was in some way connected 

 with the disease, and, apparently, as an active agent in its production. 

 But for some reason, still unknown, after August Ist, 1880, the 

 CTilture experiments undertaken were not successful, and the matter 

 was dropped for the time, on account of other work. A pure culture 

 of a Bacillus had, however, been made from the affected plants, and 

 the disease was experimentally produced by the use of this artificial 

 culture. Sterilized-water was used in exactly the same manner as a 

 check upon the former. 





Wishing to ascertain the conditions of things in the wintpr. some 

 broom-corn seed was planted in February, 1887, in the green-house, 

 and April 6th, 1887, Mr. M. B. Waite, a student, under my advice, 

 commenced inoculation experiments upon the young plants with 

 material taken from old diseased stalks, obtained at the time from 

 the field. This old stalk contained, in great numbers, living microbes, 

 though it was frozen hard when collected. There were also many 

 spores recognizable by their peculiar refractive properties and uni- 

 form shape. The cultures from this old material were not always 



