ATTITUDE OF PATHOLOGISTS AND. BACTERIOLOGISTS. 19 
yellow disease of beets, grease spot of beans, gangrene of potato, etc. The text is very 
“brief and closely follows Prillieux, except in case of the spot disease of beans, which is 
based on Delacroix’s own work. 
In the second revised edition of his large Text Book, issued in 1901, Dr. Sternberg 
mentions bacterial plant diseases for the first time, devoting 7 pages to the subject, quoting 
exclusively from the publications of Smith and Waite. 
Chester’s book (1901) includes descriptions of a few plant parasites, but does not 
venture any statements as to pathogenesis. 
In their large Treatise published in 1902, Miquel and Cambier devote 10 pages out 
of 1059 to the micro-organisms of plants. They mention 28 species as being of more or less 
interest in this connection. For general remarks by these authors on the uncertainties 
hanging over this subject, see citation in the preface to vol. I. 
Van Hall’s Thesis (1902) maintains the existence of bacterial diseases as proved 
beyond dispute. He mentions many diseases, having a very good grasp of the literature; 
and admits the following 15 as of clearly-established bacterial origin: The black vein 
disease of crucifers due to Ps. campestris; the wilt of Solanaceae due to B. solanacearum, 
the wilt of cucurbits due to Bacillus tracheiphilus; the yellow disease of hyacinths due to 
Ps. hyacinthi; the bacterial gummosis of sugar-beets due to B. betae; the maize disease 
due to Ps. stewarti; pear-blight due to Bacillus amylovorus; lilac-blight due to Ps. syringae; 
the olive tubercle due to B. oleae; the spot disease of beans due to Ps. phaseoli; potato-rot 
due to various bacteria (B. solaniperda, B. solanacearum, B. atrosepticus, etc.); carrot-rot 
due to B. carotovorus; turnip-rot due to Ps. destructans; iris-rot due to Ps. iridis and 
B. omnivorus; hyacinth-rot due to B. hyacinthi septicus. 
The original matter in this thesis will be discussed under the various diseases. 
In 1903, in the second edition of his Vorlesungen, Fischer repeats many of the inad- 
missible statements of his earlier edition, but, nevertheless, gives several pages to a review 
of a few bacterial disease of plants, dealing briefly with the rot of fleshy roots, potato-rot, 
the black-rot of cabbage, the mosaic disease of tobacco, and tree-cancers. Concerning the 
latter we have the following: 
Bacteria as the cause of cankers are unknown, for the Bacillus oleae which is said to cause the 
canker-like swellings of the olive-tree is no more legitimatized by pathological experiment than many 
other bacteria described as pathogenic for plants. 
It is fitting that these citations should end as they began, with Sorauer’s Pflanzen- 
krankheiten. The second volume of the third edition devotes many pages to the subject 
of bacterial diseases of plants. This purely didactic review published in 1905, contains 
the best summary in any general treatise on plant diseases. About 70 bacterial diseases 
are considered. The statements in it, carefully as the literature has been gone over by Dr. 
Lindau, show, however, perhaps as clearly as anything, the great need for a re-examination 
of the whole subject by some one experimentally familiar with it. 
Most of the conclusions I have cited in this chapter are to be regarded simply as 
ex cathedra judgments, or to put it somewhat differently they are to be regarded only as 
so many evidences respecting the ability of the particular writers to reason logically and 
arrive at sound conclusions from a maze of contradictory statements. In other words 
they are literary or legal judgments rather than scientific ones. A good judge must have 
not only a keen, well-balanced mind, but he must also know the case and the law. Very 
few of the writers I have cited appear to have had any extensive acquaintance with this 
class of diseases, or with the rules of evidence guiding in pathology, and those who have 
rendered adverse judgments seem to have had none whatever, 7. ¢., they made few observa- 
tions and no experiments, or only some irrelevant ones. It is no wonder, therefore, that 
the insight of some of these writers has been much shrewder than that of others, or that 
most of them should have mingled fact and fancy in nearly equal portions in what they 
