DISEASES AND ENEMIES. 
539 
The sense of smell is also appealed to, as a peculiar 
foul and extremely characteristic odour now escapes 
from the diseased combs. This is difficult to describe, but 
it reminds me of offensive glue; while it is notunlike 
that from guano. The odour is not always present 
with equal intensity ; sometimes it is only observable 
when the hive is opened ; at others, it is quite pro- 
nounced, even 3ft. or 4ft. from the entrance. As the 
disease spreads, the bees lose energy, but in most 
cases become unusually earnest in fanning at their 
hive door. Dead larvae or pupae, in growing numbers, 
occupy cells that should have been vacated to receive 
eggs, and, being irregularly scattered, force the 
latter to be distributed unmethodically, and not 
as in a healthy stock. Should any attempt be made 
at removing a dead larva which has assumed 
the coffee-coloured stage, the remains, tenaciously 
adhering to the cell wall, will stretch out into long 
and thin strings, somewhat like half-dried glue. The 
microscopist can easily explain this. The thin, 
chitinous, aerating sacs and tracheae (page 33, Vol. I.) 
do not undergo decomposition at all easily, and these 
remaining occasion the peculiarity referred to. The 
disease is terribly infectious, and, once started, soon 
spreads from cell to cell, and not infrequently from 
stock to stock, until, in the whole apiary, perhaps 
not even one escapes. 
Some of the symptoms described may appear in 
the absence of disease, when the brood has died from 
chill ; but then the characteristic odour is absent, and 
the discoloration in the larvae is usually a change to a 
grey, and not a brown. The microscope immediately 
