326 
the present year one firm of painters lost over £200 in consequence 
of the appearance of the fungus in a large number of cucumber- 
houses painted with expensive protective paint. All the work 
had to be done over again, and in some instances the second coat 
had to be removed and a third coat applied. 
The surface of the paint is not at all broken up, or in any way 
injured by the fungus, and the amount of discoloration depends on 
the relative quantity and spread of the mycelium. 
en the spores of the fungus are sown on a streak of wet white 
paint, a faint roseate tint appears in about a week’s time, and within 
three weeks fruit is produced in abundance, and the deep purple 
characteristic blotches are well developed. 
Spores sown on a thin smear of pure linseed oil germinate as 
readily as in paint, but the mycelium remains colourless, and, so 
far, no fruit has been produced. The result is the same when 
the spores germinate in ordinary nutritive media or in water. 
0 germination takes place when the spores are sown on a streak 
of pure white lead, or carbonate of lead. Hence this substance 
alone is not a suitable medium for the growth of the fungus, 
although its presence is necessary to enable the plant to complete 
its normal course of development, and it is also the constituent from 
which the fungus produces as a by-product the purple-red colouring 
matter, which is collected in oily-looking drops within the cells of 
the mycelium, the cell-walls themselves remaining colourless. The 
colour enegests that the white carbonate of lead undergoes 
some chemical change induced by the presence of the fungus, result- 
ing in the formation of red oxide of lead. This matter, however, 
requires careful investigation. 
he presence of two per cent. of carbolic acid in paint completely 
arrests the development of the fungus. 
ydrogen peroxide bleaches, or at all events considerably reduces 
the red colour without injuring the paint, but this is not a practicable 
remedy on an extensive scale, 
The following is a technical description of the fungus :— 
Phoma pigmentivora, Massee, Maculae suborbiculares, deter- 
minatae, laete rosaceae vel rosaceo-purpureae, 1-8 cm. diametro. 
Perithecia in maculis laxe gregaria vel confertiuscula, vix prominula, 
purpureoatra, subglobosa, contextu parenchymatico, ostiolo vix 
pillato donata, 125-1504 diametro, Sporulae ellipsoideae 
fiyalliiads 00 Se bhp = : ; 
EXPLANATION oF PLATE, 
Figs. 1 and ~ showing discoloured patches produced by the fungus. 
ze 
at. size, 
Fig. 3. Patches of the fungus three weeks after the spores were 
sown on a thin film of wet paint. Nat. size. 
Fig. 4, Perithecium of fungus. Highly magnified. 
Fig. 5, Mouth or opening of a perithecium. Highly magnified. 
Fig. 6, Spores of fungus. Highly magnified. | 
