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The second point is of greater importance, and Shapovalov 
here refers to Kunkel’s(*) plates xxxrx, xii, and xii in 
support of his statement. Plate xxxrx figures a section through 
deeper tissues. It is not clear whether Shapovalov claims to have 
found such plasmodia in Skin spot pustules or not. He speaks of 
the “ path of infection ” and of “ infection ” which extends into 
the cells, but what this really means it is impossible to say. 
We can only conclude that no definite plasmodia have been 
found in the pustules and that, consequently, the case for analogy 
_ between the two diseases is unproven. 
The last of the links in the author’s chain of evidence consists 
of his failure to reproduce Skin spot with cultures of Oospora 
pustulans. He gives no account of his inoculation experiments, 
but disposes of them in the sentence “The writer’s laboratory 
inoculation of healthy potato tubers with 0. pustulans, like those 
reported by Owen(’), gave entirely negative results.’” No pot or 
field experiments appear to have been carried out, and in view 
of the fact that Miss Owen certainly obtained strong indications 
of pathogenicity in her field experiments, this summary dismissal 
of the organism 1s very premature, Had more positive results 
ACCOUNT OF EXPERIMENTAL Work. 
Isolation of Oospora pustulans. Some typical Skin spot 
material from King Edward and Ally seed potatoes was easily 
