112 Early Work in North America 



begun the cultivation of bacteria on solid substratum and hope 

 soon to arrange culture tubes for their cultivation in fluids. I 

 only today planted my pear bacteria and so do not yet know how 

 I shall succeed with them." By August 17 he was announcing that 

 he would "present only one paper to the American Association, 

 which [would] be on the absolute proof that pear blight is due to 

 bacteria." This was entitled " Proof that Bacteria are the direct 

 cause of the disease in trees known as Pear Blight," ®^ and, being 

 read at Ann Arbor, supplied the basis for Erwin Smith's review of 

 "Recent Literature concerning Pear Blight."^" In 1884 Arthur 

 had found that he "could transfer the disease more certainly by 

 cutting up a little of a diseased limb in a small amount of water. 

 The water would become slightly milky with the liberated germs, 

 and to inoculate a limb [he} used a small drop of this milky 

 water." ^^ During 1885 he used " sterilized solutions of starch, 

 corn meal, etc." to grow the " micrococcus " and, after filtering the 

 culture liquid through porcelain, reproduced the blight with the 

 residue and not the filtrate.^* This artificial culture technique, 

 followed by pure culture experiments which as we shall see Smith 

 later believed were " probably " pure cultures, was the reason why 

 he believed that Arthur had "carried the work considerably far- 

 ther" than Burrill. Smith not only studied Arthur's paper but 

 also had "personal conversations with him" on the subject. In 

 January the New York experiment station botanist had visited 

 Professor Spalding's "good department" at the University of 

 Michigan; and he had written Bessey that Spalding was building 

 the department " in the right manner and in the right direction. 

 He intends," Arthur wrote, "to visit Europe in a year or so to 

 become more familiar with the German methods." ^' 



On August 26, in University Building at Ann Arbor, Dr. Bessey 

 addressed the Society for the Promotion of Agricultural Science 

 on " The Demands Made by Agriculture upon the Science of 

 Botany." ^'^ Three coordinate extensions of laboratory research 



^^ Proc. Amer. Assoc. Adv. Sd. 34: 295-298, 1885; Botanical Gazette 10 (9 and 

 10): 343-345, 1885. 



""^ Michigan Horticulturist 1(2): 34-36, 1885. 



"J. C. Arthur, Pear blight, Proc. Amer. Pom. Sac. for 1885: 44-47, 1886. 



^^ E. F. Smith, Michigan Horticulturist 1(2): 34-36. 



^^ Letter, Arthur to Bessey, January 30, 1885. 



*^ Proc. 6th Meet. Soc. Prom. Agric. Sci., of 1885, Manhattan, Kansas, 16-18, 

 1886. 



