The Aberystiryth Aren 
to them over the hills from Radnorshire; while others, in the north, 
make similar allegations regarding Merioneth. There is always a marked 
tendency to blame other districts or farms for troubles that have very 
probably originated at home: and some people carried this to the 
length of blaming some English rams that had been used in the Area, 
as the source of trouble. 
It is my opinion that the disease is at all times endemic to a greater 
or lesser extent, but what factors govern its sudden increase I am unable 
to say: investigation at the period of an outbreak would probably 
vield the required information. From statements made by several of 
the older men, it is evident that another very similar outbreak occurred 
in 1881, or thereabouts. It is by no means easy to obtain the correct 
dates for past occurrences, among a people who seldom keep any records. 
All agree that this outbreak was "some years ago’’; others are fairly 
certain that it was “ten or fifteen years ago.” Fortunately one farmer 
had entered and dated his losses and kept the old books; while the 
local veterinary surgeons were able to help me to some extent. 
Losses ranged from one or two up to fifty or sixty per flock during 
1901—2. One owner had sixty ewes affected out of a flock of 200, 
but by standing them in pens in which quick lime had been spread, and 
by constantly repeating this process, many larvae appear to have been 
sneezed out and no losses occurred. The whole of the uplands appear 
to have been involved, though in varying degree. 
The general health of the flock and the state ot the individual is 
considered to have played an important part in relation to losses (as 
is usual with parasitic diseases). Flocks kept in good condition suffered 
much less than those in a poor state, while more ewes died than wethers, 
the former being weakened by lambing and suckling. One or two men 
claim to have noted slight cases since 1904. I have myself observed 
sheep behaving in a suspicious manner, placing their noses to the 
ground, etc., and 1 instituted further enquiries in .1915, this time among 
butchers’ assistants and slaughter-house men. As a result, I obtained, 
during May. two infected heads, one from the south of the Area, and 
another from a few miles beyond the southern boundary; while in 
April 1916 a third was sent from 8. Cardiganshire, In each case the 
number of larvae present was small. It is therefore evident that the 
tlv is normally present in small numbers, but, as is the case with other 
insects, liable to become suddenly abundant. 
How far the purchase of infected sheep may tend to spread this pest 
by importing it into fresh districts remains to be proved. A farm which 
