580 
Journal of Agricultural Research 
Vol. XI, No. ii 
the stems of six of these plants up to the terminal bud, and, in one case, 
growth was obtained from the seed capsules. The two other plants 
showed growth up to within i inch of the terminal bud. Sections taken 
from near the top of the stem of a plant which had just wilted, and stained 
with “Pianeze Illb stain” (24) showed the fungus hyphae in the vascu¬ 
lar system but not in the cortex. The method used in staining was 
varied somewhat from that described by Vaughan ( 24 ). The slides were 
passed from xylol through absolute and 95 per cent alcohol into the 
stain, where they were allowed to remain overnight. They were then 
washed rapidly in water to remove loose stain and detained in 95 per 
cent alcohol until the desired point was reached. After detaining they 
were passed through absolute alcohol and xylol and mounted in balsam 
Fig. 5 .—Longitudinal section of woody tissues of susceptible flax plant showing the invading hyphae 
of Fusarium Uni. 
in the regular manner. Excellent results were obtained by this method 
of staining. 
There seems to be very little reaction on the part of the protoplasm 
of the susceptible host toward checking the invasion 1 by the fungus. The 
fungus grows rapidly within the tissues (fig. 5), and sometimes micro- 
conidia are produced in the vascular cells of the host plant (fig. 6). 
Some of the vessels may, in rare cases, become almost clogged with fungus 
hyphae (fig. 5), but this is so rare that it would hardly seem possible 
that the wilting could be due to the cutting off of the water supply by 
this means (fig, 7). Gilman (14) believes that the yellowing of cabbage 
is due to the slow drain made by Fusarium congluiinans on the water sup¬ 
ply combined with the high temperature, which causes an increased 
