126 OBSERVATIONS ON THE CALIFORNIA VINE DISEASE 
The degeneration of the chloroplasts, like the incrusting of the 
primordial utricle, proceeds further in the palisade than in the 
lacunose tissue. In the cells of the lacunose tissue the chloro- 
plasts do not, as a rule, form large plasmodium-like aggregates. 
They become vacuolate, but usually without distending to any 
extent, and, in the row of cells next the palisade layer, when the 
lumen is free, are inclined to fragment or degenerate into oil- 
like bodies. (PLATE 3, FIGURES 3, 4; PLATE 4, FIGURES 3, 5.) 
The vessels of the minor bundles of the leaves are occluded 
more or less by granular or homogeneous matter, and the same 
may be said of the bast, cortical parenchyma, collenchyma, and 
epidermis of the main veins. (PLATE 3, FIGURE 5.) 
Thylloses are often present in the vessels of the main vein. 
(PLATE 4, FIGURE I.) 
Viala and Sauvageau, in their study of the California vine 
disease, remark that a “section cut through an apparently uni- 
formly diseased area often shows breaches of continuity due to 
healthy starch-replete cells which may be coextensive with the 
diseased tissue.” "This observation, while perfectly correct, 
applies only to diseased leaves taken from varieties of grape- 
vines bearing black grapes. In these varieties diseased centers 
may be surrounded directly by red aureolae,? and the cells іп 
this reddened tissue are replete with starch. When therefore, 
Ше aureolae of diseased centers are contiguous, or we have an 
intervenar stripe dying irregularly, the prenecrotic color being 
red, such an irregular alternation of starch-replete and starch- 
free cells may occur. The presence of starch, however, is patho- 
gnomonic, and not indicative of health, as the authors just quoted 
believed. When, as occasionally happens, the dead tissue abuts 
directly on that which is still green, without apparently any inter- 
vening morbid cells, we do not find such a thing as starch- 
replete and starch-free cells. In fact, in section, what appeared 
macroscopically as a decided line of demarcation is certainly 
шекер тенден. 
1 Viala, Sa & Sauvageau, С. La Brunissure et la Maladie de Californie. 
Ann, Ecole TR Montpellier, 7: тот. 1892. [Translation.] 
“Тһе reddening of vine leaves, so far as I have meses is always accom 
panied by a starch congestion. See Ravaz, L., & Roos, L. Le Rougeot de i 
vigne. Progrès Agricole 44: 363-370, 392-398. 1905. А 
