14 CROWN-GALL OF PLANTS. 



which may also induce infections independently of them. Corvo's 

 statements do not appear to have received any attention from 

 students of Phylloxera in France or elsewhere, and his bacteriological 

 technic is wholly negligible. '^ The organism is supposed to be a 

 bacillus. It was obtained [sic] by putting the brown slime and 

 fragments of tissue into flasks of vine juice diluted with distilled 

 water, no mention being made of any surface sterilization of the frag- 

 ments or of an}^ preliminar}^ sterilization of the culture fluid. The 

 fluid clouded after a few days, and the infections were then obtained 

 by plunging split vine shoots into this yellowish rotting fluid ; again it 

 would appear without surface disinfection. The results obtained 

 appear to have been limited to a yellow-brown stain in the tissues, 

 which is said to be the striking characteristic of the disease. In this 

 stained portion, naturally, organisms were found. 



In 1889 Cuboni published a note on the subject in the Atti della 

 Reale Accademia del Lincei (Rendiconti), Rome, vol. 5, p. 571. He 

 reported finding an abundance of bacteria in the tubercles of the 

 vine, but they appear to have been limited to dead portions. The 

 important part of his paper is included in the following citation: 



The examination of microscopic sections made from scabby shoots collected the 

 previous year and preserved in alcohol has demonstrated that in fact in all the tuber- 

 cles are to be found masses of bacteria wholly identical with those which are to be 

 observed in the tubercles of the olive. These bacteria are united into zoogloese by a 

 mucilaginous substance insoluble in alcohol, filling the small canals or lacunae which 

 are found scattered irregularly throughout the tubercle. The dimensions of the bac- 

 teria vary from 1 to 1.5 /i and are about 0.3 /x broad. In the unstained sections placed 

 in glycerine these bacteria are strongly refringent to light; treated with methyl violet 

 they stain quite feebly. 



The cells which surround the lacunae occupied by the bacteria are dead and in 

 great part corroded. The walls of the cells remaining are of a yellowish-brown color, 

 BO that the naked eye is able to recognize in a section the nodules and the little canals 

 where the colonies of the bacteria occur. Surrounding the lacunae, i. e., beyond the 

 zone of dead cells, are found parenchyma cells full of protoplasm with nuclei, many 

 cells filled with starch granules, and also here and there strata of suberized cells alter- 

 nating with strands of large bast fibers, and finally the woody elements, especially 

 tracheids, contorted in an odd fashion and the whole arranged in an irregular manner, 

 80 that it is often difficult to orient one's self as to the genesis of the various elements. 



No mention is made of any cultures or inoculations. 

 In 1889 Trevisan published for the above-indicated bacteria the 

 name Bacillus ampelopsorae, drawing his account entirely from the 

 notes by Cuboni and Savastano's reference to Corvo. At least 

 there is no evidence that Trevisan himself took the trouble to make 

 even a cursory microscopic examination, his habit being to name 

 everything left unnamed by others, without troubling himself to 



a Petri makes no mention of Corvo, but states (Annalos Mycologiei, Juno, 1909) that in (he galls of 

 Phylloxera he found scarcely any bacteria: "The bacteria were very rare, and never have I been able to 

 Isolate from the galls the Bacillus vitis." 

 213 



