ATTITUDE OF PATHOLOGISTS AND BACTERIOLOGISTS. II 
and Berthold, with the remark that recent experiments by van Tieghem on potato-tubers, 
bean-seeds, cactus-stems, etc., seem to confirm these results. 
Otherwise expressed, these facts may be stated as follows: As a rule, saprophytic bacteria may, 
under special conditions, attack, make sick, and destroy living plant tissues as facultative parasites. 
In the third edition of Zopf’s Spaltpilze, published in 1885, bacterial diseases of plants 
are discussed as follows: 
Much rarer [than in menand animals] are the cases in which we can speak of the genuine parasitic 
action of schizomycetesin plant-organs. The best-known example is the familiar disease of potato- 
tubers known as “wet-rot” caused by the butyric acid ferment (Clostridium bulyricum), through 
which the tissues of the potato are entirely destroyed and converted into a vile smelling fluid-mass 
(Reinke and Berthold). It remains to be seen whether the phenomenon known in Holland as ‘‘the 
yellow disease of hyacinths,”’ and recently described by Wakker, belongs here strictly speaking. Its 
characteristics are the appearance of enormous numbers of yellow schizomycetous colonies in the 
vessels and (at blossoming time) also in the intercellular spaces and cells of the parenchyma. 
Perhaps the rarity of schizomycetous diseases of plants lies in the generally acid reaction of 
the juices of plants, perhaps also in their lower temperature as compared with the animal body, and 
finally the formation of protective cork is perhaps also to be considered (p. 3). 
In the second edition of De Bary’s Vorlesungen (1887) Arthur is said to have confirmed 
and extended Burrill’s work on pear-blight. 
In the second edition of his Handbook, published in 1886, Sorauer devotes 38 pages to 
diseases due to bacteria, namely, to rot of the potato, white rot of hyacinth bulbs, rot of 
onion bulbs, Comes’s gummosis of the tomato, Prillieux’s rose-red wheat grains, and various 
stem and leaf reddenings. These pages deal with field appearances, the results of micro- 
scopic examinations, and to a limited extent with what I have designated in vol. I as direct 
infection experiments. Sorauer accepts the doctrine of bacterial disease of plants without 
reserve and says: ‘‘Beyond doubt, in course of time, a large number of rot diseases will 
be recognized.”’ Of exact bacteriological methods there are no suggestions in this book. 
Dr. Sorauer’s own observations appear to have been limited to microscopic examinations 
and a repetition of such crude infections as were made by Davaine, Hallier, Reinke and 
Berthold, van Tieghem, and others. The bacteriosis which he had in mind is that which 
occurs when tubers and bulbs are exposed to excessive moisture, with a restricted supply 
of oxygen. From his own observations and experiments on potatoes, he could say with 
reasonable assurance that ‘‘the wet-rot or rot may be produced artificially without the aid 
of Phytophthora by inoculating bacteria into sound tubers. The decomposition phenomena 
of the two diseases are essentially different.’ He had also observed that the bacteria could 
penetrate through the open lenticels into the tubers. 
The statements in Sorauer’s book on Die Schaden der Einheimischen Kulturpflanzen 
(1888) are essentially the same as in his Handbook, only much more condensed. His gen- 
eral standpoint is expressed in the following sentence: ‘‘ The bacteria are certainly much 
more dangerous to living plants than has hitherto been recognized.” 
De Toni and Trevisan in vol. VIII of Saccardo’s Sylloge Fungorum (1889) gave 
short descriptions of all the species of Schizomycetes known to literature. 
Under bacillus ‘‘Sectio 6 species endophytobiae, destruentes,”’ the following species 
are included: Bacillus vuillemini Trev., B. oleae (Arcang.) Trev., B. ampelopsorae Trev., 
B. radicicola Beyerinck, B. hyacinthi (Wakk.) Trev., B. hyacinthi septicus Heinz, B. sorghi 
Kell., B. amylovorus (Burr.) Trev. 
Laurent, writing in 1889, has the following: 
Many fungi which invade the higher plants have the property (proprieté) of perforating the 
cell membranes by the intervention without doubt of a special zymase. The germs of the ordinary 
bacteria could easily penetrate into the leaves by way of the stomata when they are brought there 
by the wind or other agents. But having reached the stomatic chamber, they would have to traverse 
the cell membranes or to insinuate themselves between the cells. In order that this last mode of 
