146 Pathologist U. S. Department of Agriculture 



inck's paper of 1888." During the 1880's botanists were still 

 arguing the improbability of bacterial diseases of plants. A part 

 of their theory was that " the reaction of plant juices is acid and 

 bacteria grow only on alkaline media." Susceptible host plants as 

 well as parasites, however, were being investigated; and some of 

 the younger botanists were beginning to challenge points of view 

 of their elders. 



In 1889 Smith reviewed in the Journal of Mycology ^'^ Dr. 

 Robert Hartig's Lehrhuch der Baumkrankheiten and observed that 

 the book went further than its title in that diseases and parasitic 

 fungi which attack grains, vegetables, and other herbaceous plants 

 were described along with diseases of forest trees. Occasionally 

 the reviewer met "a questionable statement" and his criticism 

 read: 



Under Gymnosporcing'uim four species are mentioned — G. conkum 

 {juniperim/m) , clavariaejorme, Sabiuae {jus cum), and tre»ieUo!des. The 

 author thinks a further investigation of the forms thus far known and 

 described is desirable, as the results of some experiments instituted by him 

 do not agree with those commonly accepted. No mention is made of the 

 labors of Dr. Farlow or of Dr. Thaxter. 



Under bacteria Dr. Kartig urges the commonly accepted view that the 

 acid reaction of most plants is unfavorable to their growth and develop- 

 ment, and evidently thinks they play a very unimportant role in the pro- 

 duction of plant diseases. They have been found as parasites, he says, 

 only in thin-walled, soft parenchymatous tissue, such as bulbs and tubers, 

 and here are often preceded by fungi. Even in Waacker's hyacinth disease 

 (the yellow, slimy bacteriosis) " the bacteria do not attack entirely sound, 

 well-ripened bulbs under normal conditions," but only those that have 

 been wounded or previously attacked by fungi ; especially by a hypho- 

 mycetous fungus, which is almost always associated with this bacteriosis. 

 In damp places the bacteria enter the wounds and cause the rot. The 

 following paragraph on pear blight will hardly pass muster, and was 

 certainly not to be expected in a handbook published in 1889. AH the 

 recent American publications on this subject, especially the papers by Dr. 

 Arthur, appear to have escaped the author's attention. 



"" Recently a disease of pear and apple trees, called blight, has been 

 described by [T.] J. BurriU in Urbana, 111., the cause of which this investi- 

 gator ascribes to the invasion of a bacterium. The disease appears to bear 

 a resemblance to the tree canker {Baumkrebs) caused by Nectria ditissima, 

 and since in this fungus small bacteria-like gonidia are produced in great 

 numbers in the bark, it becomes necessary to inquire first of all whether 

 this disease has not been wrongly ascribed to a schizomycete." 



5 (3): 174-177, 1889. 



