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parasite preying upon the Helminthosporium mycelium; but numerous 
tests convinced me that such was not the case, but that what really occurs 
is that the old aerial mycelium dissolves (probably by auto-digestion). All 
stages of this disorganization can be followed under the immersion lens in 
stained preparations, where the disorganized filament stains with the gen- 
tian violet but is seen to be amorphous and without protoplasmic content. 
These phenomena appear to be limited to the aerial mycelium, but were 
Fic. 7.—Various views (a and b, low power, c—o, high power) of mycelium of H. No. 1 in 
senescence: a and b showing dissolution to fine threads, 6 with a conidiophore still attached; 
c—h and m, empty mycelial cells adjacent to cells nearly dissolved; i and 7, protoplasmic 
cells adjacent to empty cells; k and /, fine mycelial outgrowths from protoplasmic cells; » and 
o, fine mycelial threads growing from the protoplasmic cells and through old empty cells; p, 
bits of mycelium, as seen with the immersion lens, showing the nuclei. 
observed on many strains of Helminthosporium. Autodigestion of my- 
celium doubtless occurs in the case of wood-rotting fungi, as is evidenced 
by the absence of mycelium where it was previously known to be, and it 
may be of common occurrence in other fungi. It certainly occurs when 
two hyphae join by anastomosis, and in the union of sexual organs. Grow- 
ing-through of the mycelium, as noted above, and even conidia-formation 
within the old cell are common in Saprolegnia, and have been noted in 
