294. REPORT—190 4. 
In underground workings, however, the temperature, &e., are fre- 
quently such that the eggs will quickly hatch and the larve develop ; 
there are very seldom any ‘sanitary arrangements,’ and the darkness 
renders it difficult to avoid coming into contact with fecal material. 
(1) Lemperature.—There is need of much more collected information 
respecting the actual temperatures found in coal-mines. It would, how- 
ever, appear that a temperature of 70° F. or more is found in parts of 
most pits, while temperatures of 80° F’. are not uncommon. 
The eggs may hatch and the larve reach the encapsuled stage at any 
temperature from 60° F. to about 95°-100° F. ; the optimum temperature 
seems to be about 75°-80°. Below 60° the eggs may occasionally hatch, 
but the larve will not grow to the infective stage. 
Once the larve have reached the infective stage they seem to be 
largely indifferent as to temperature : they certainly live longer at room 
temperature than at 98°, but not longer than at about 70° F. 
(2) Moistwre.—Some water is to be found about all mines ; even if 
there is very little standing water in the roads there is enough to produce 
a muddy condition at places. The worm cannot be propagated in com- 
plete absence of moisture, and the larve are soon killed by drying ; but 
parts, at any rate, of most mines are sufficiently wet to allow the larve to 
grow freely. 
On the other hand there may be too much water to allow the eggs to 
hatch. Eggs contained in feces covered with a shallow layer of water 
will not produce larvee at any temperature. Once hatched, however, the 
larvee flourish in water. 
(3) Hilth.—Coal-mines appear to be a good deal cleaner, from a sani- 
tary point of view, than metalliferous mines. This is in part due to the 
fact that at the face feces are generally deposited in the goaf! and 
covered with coal dust ; and in part to the greater prevalence of dust 
and to the larger area. 
There is, however, no failure of sufficient fecal contamination. In 
many instances small partly disused roads are made use of by the men 
for the purpose of relieving their bowels. This usage is particularly 
dangerous. 
Duration of the Infection in Man. 
Well-authenticated cases of infection, lasting more than six years after 
the last possible contact with infected materials, have been recorded. 
Viability of the Worm in Mines. 
Encapsuled larve have lived in the Gordon Laboratory for twelve 
months (still alive) at 68° F. There is no direct evidence as to how 
long they may live underground, but in water obtained from two North 
Staffordshire mines they suffered no ill effect, and were observed for several 
weeks. 
Natural Conditions in Mines which are unfavourable to the Worm. 
Parts of all, and nearly the whole of some mines, fail to produce the 
combination of dampness and warmth favourable to the hatching of eggs. 
' The ‘goaf’ or ‘gob’ is the worked part of a mine, where the coal has been 
removed, The supporting timbers are withdrawn, and the roof is allowed to close 
on to the floor. 
