40 MICROBES, FERMENTS, AND MOULDS. 
by a fungus, but by a degeneration which is either 
spontaneous or, as Pirotta and Cugini suggest, the 
work of bacteria, and which consists in the trans- 
formation of the cellulose and starch of the plant 
into dextrine, as Comes asserts, or, according to Pirotta, 
into tannin. 
This disease appears in three stages: (1) a simple 
discolouration of the sap, which assumes a tawny 
black shade without checking vegetation; (2) a begin- 
ning of necrosis, which renders the plant unhealthy ; 
(8) a complete necrosis, which affects the woody parts 
and arrests the growth of the plant. 
This disease is contagious, which leads us to 
believe that if it is not produced by a fungus, it is 
at any rate due to the development of a bacterium— 
that is, of a microbe. 
The remedy indicated by Italian naturalists con- 
sists in the application of salts of potassium, which 
may be extracted at small cost from the ashes of the 
vine branches which are burnt upon the spot. 
Resleria hypogea, or Rot.—This parasitic fungus is 
found on the vine-roots, and has been recently studied 
by Prillieux. The vine affected by this parasite 
languishes for some years and then dies. The evil 
spreads by means of the roots to adjoining stocks, 
and the parts affected spread like the patches formed 
by the phylloxera. The roots rot away. This disease 
has been widely spread in Haute Marne. 
This small fungus is distinct from one which bears 
