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POPULAR SCIENCE REVIEW. 
Mysore almost as long as the “coffee-leaf disease.” Mr. Gr. 
Porter says that “ it is very prevalent in the Mulnad portions 
(and more especially in the Kadur district) of the Mysore 
country. It is known as the 4 kole roga,’ or 4 black rot,’ and 
not only does it attack coffee, but it does great havoc in the betel- 
nut gardens. He was told by the natives that they had hardly 
ever known a wet season without it, some years worse than 
others. It is this disease that coffee suffers far more from than 
from that of the Hemileia vcistatrix. It makes its appearance 
about July, when the leaves of the trees affected by it get 
covered with a slimy gelatinous matter, and turning black drop 
off ; the berries likewise rot and fall in clusters. He estimates 
that the planters lose nearly one quarter of their crop each 
year by this plague. Grangs were sent round last monsoon to 
collect the diseased leaves, which were carried off the estate and 
burnt ; and although this did some good, it was not the means of 
abating it to any extent.” 
The leaves affected with this 44 rot ” are spotted on the under 
surface with large greyish-white irregular patches, sometimes 
occupying nearly the whole surface, sometimes in spots limited 
by the larger veins (PI. CXXXV. fig. a). These patches are 
quite smooth to the naked eye, with all the appearance of a 
superficial incrustation. When moistened, the entire spot can 
be removed with the point of a lancet, by stripping it in a 
delicate hyaline film, somewhat like a film of gold-beater’s skin, 
showing no attachment to the leaf, unless of a very slender and 
superficial nature ; indeed, the film may be rolled up under the 
thumb and finger. Under the microscope this film is found to con- 
sist of a closely interwoven web of hyaline septate filaments, often 
branched, and crossing in all directions (PI. CXXXV. fig. b). 
They are usually from *005 to *0075 of amillemetre in diameter. 
On the upper surface these threads are studded at irregular in- 
tervals with small globose echinulate spores, which are seated 
upon the threads, without any visible pedicel, although when 
first formed there appears to be a short stem, which is ultimately 
absorbed (PL CXXXV. fig. c). These spores are about equal 
in diameter to the diameter of the threads. The threads and 
spores seem to be agglutinated together into a film by some 
gelatinous medium, so that not a spore or thread can be removed 
from the mass without difficulty. In this feature the 44 rot ” 
differs from nearly all the Mucedines , in which the spores are 
so slightly attached that they float away on the application of 
moisture, whilst in the present instance no application of fluid 
avails to disturb a single spore. 
In order to examine the fungus in as complete a manner as 
possible, a portion of the leaf is immersed for twelve hours in 
water, but this does not dissolve the mucus so as to free the 
