526 Massee. — On Trichosphaeria Sacchari , Mass.; 
itself in diseased canes, it seems probable that the fungus 
usually effects an entrance at these points. 
The hyphae belonging to the macroconidium-stage very 
frequently follow the middle lamellae for some distance, 
giving off lateral branches that pass into the cells through 
a pit in the wall, the cavity of which does not become at 
all enlarged, the closing membrane alone being dissolved. 
When the tip of a hyphae extending along the surface of 
the wall passes over a pit, a minute papilla projects into the 
cavity and grows through the pit as a delicate strand about 
i*5 fji thick ; immediately on emerging at the opposite side 
of the wall, the delicate filament assumes a spherical form 
5-6 ijl diameter, and then continues elongating as a hypha of 
equal thickness with the one from which it originated on the 
opposite side of the wall. The hyphae do not cling to the 
wall inside the cell : some branches remain in the cell and 
utilize its contents ; others grow straight across until they 
come in contact with the opposite wall, and if the growing 
point does not happen to alight on a pit at once, the hypha 
follows the surface of the wall, searching for one, through 
which it passes by a narrow neck into an adjoining cell ; or 
very frequently follows the middle lamella. By this method 
the hyphae travel quickly through the tissues. In some 
preparations the hyphae in following the middle lamella are 
seen to take a sinuous course, as if searching for the sparsely 
scattered pits, and not unfrequently five or six branches enter 
into, and grow across a cell, all originating from a single 
hypha growing along the line of the middle lamella (Figs. 
12, 13). Very good preparations showing the hyphae passing 
through the cell-wall, as described above, result from first 
soaking the sections for an hour in a five per cent, solution 
of potassic hydrate, washing thoroughly in water to get rid 
of the potash, and afterwards staining with Bismarck brown 
or picro-nigrosin. Very old hyphae are naturally of a pale 
brown colour, and require no staining. 
