[Vor. 3 
26 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
be discussed, in order that the physiological relations between 
host and parasite may be understood more clearly. А brief 
resumé of the literature on cabbage yellows will show the 
state of our knowledge of this disease at the time these inves- 
tigations were taken up. 
History oF THE DISEASE 
The disease was first reported by Smith (799, 7997), ав occur- 
ring in New York State in 1895. He found the trouble ex- 
ceedingly severe, threatening ‘‘to put an end to the success- 
ful growing of eabbages in considerable districts.”’ He con- 
sidered that the disease was ‘‘due to a soil Fusarium” but 
made no inoeulation experiments. Aside from this observa- 
tion his only contribution to our knowledge of the disease was 
in relation to its persistence in the soil; the organism resisted 
drying in the laboratory for three and one-half years. Woods 
(799) showed that the characteristic symptom, the yellowing, 
was due to the presence of an increased amount of an oxidiz- 
ing enzyme, peroxidase, in the diseased leaf tissue. Norton 
and Symons (207) reported the presence of Ше disease in 
Maryland, but performed no experimental work. 
Harter (709), of the Bureau of Plant Industry, made inocu- 
lations of sterile soil with pure cultures of a Fusarium isolated 
from the stems of diseased cabbage plants. He was able to 
produce the characteristic symptoms in plants grown in that 
soil. In one trial, 83 per cent of these inoculations were suc- 
cessful; in a second, he reported that a large percentage of 
the plants showed typical symptoms, but no exact figure was 
given. He also made the statement that the fungus was a 
vascular parasite and formed microconidia in the vessels of the 
living plant. In addition to this paper Harter (712) has pub- 
lished merely a popular aceount of the disease. Manns (711) 
reported the disease as prevalent and destructive in Ohio but 
limited his work to field observations of a general nature. 
Jones (713, 714, 714%) in a series of papers reported the de- 
velopment of strains of winter and "kraut" types of eab- 
bage which are highly resistant to the attaek of this disease. 
These strains were developed by means of selection of sound 
