372 Proceedings of the Royal Society 
advocated ; the removal and killing of all affected fish has been 
recommended by many. On the other hand, the Tweed conservancy 
hold the opinion that the capture and removal of all fish affected 
with fungus (not in a dying state) to salt or tidal water was the 
proper course to follow, and with this opinion I fully concur. There 
is one point in this plan which may cause some disappointment. 
Supposing it proved that salmon are cured of fungus disease in the 
salt water, and that those so affected in the upper waters, were cap- 
tured and conveyed to the tidal part of the river, only those fish 
with the instinct of descending to the sea, when captured, would 
remain to he cured. Those with the instinctive desire to ascend, 
when captured, would in all probability return to the fresh water. 
Those instincts in the fsalmon are known to he both strong and 
certain, their sense of being diseased, and need of cure “ instinctively 
or otherwise ” are unknown. 
I shall now give an account of the very remarkable epidemics 
which occured at Ightham in Kent, the particulars of which were 
kindly communicated to me by Dr W. S. Church, Physician to St 
Bartholomew’s Hospital, London. They are of so much interest in 
the history of the fungus disease, that I feel warranted in bringing 
them to the notice of the Society. Ightham House dates from the 
time of King John, and the fish ponds were probably constructed 
at the same time, to supply the house with fish. The house is built 
in the form of a square, and surrounds a courtyard. The house in 
its turn is surrounded on all sides by a moat, the water in which is 
from 5 to 9 feet in depth. The present arrangement of the ponds, 
garden, &c., was probably made in the time of James I. The house 
drains into the moat, and the drains issue into it by separate open- 
ings from two sides of the square. The stream which supplies the 
ponds and moat is formed by the surface water of a small valley, but 
is principally supplied by two very fine and strong springs, which 
come out of the Kentish limestone. The stream is only about a mile 
in length before it enters the upper pond, and there is at all times a 
strong run of water in it. It is perfectly free from drainage contamin- 
ation, and enters the upper pond perfectly pure. There are two 
cottages and a small fold yard on the side of the stream, but no 
drains flow from them to the water ; the fold is in a ruinous con- 
dition, and is not in use. 
