70 
Natural History Notes.—ii1. 
(A SEQUEL To THE ForEGcoinc Paper) READ DecemBER 17TH, 1909. 
Some months ago I was invited to put together a few more 
Nature Notes as part of the programme for this evening, and so out 
of a rather limited supply of experiences of an unusual character I 
venture to lay the following before you. 
A good many years ago, in company with an old friend, | spent 
a fishing holiday on the river Usk at Usk. Amongst various 
recollections of what interested us at the time two things stand out 
rather prominently. The river was rather low and had been in this 
state for a considerable period through the spring and early summer. 
The stagnancy of the deep pools caused by this and possibly the 
crowding of Salmon in them had apparently led to a serious state of 
contamination and had resulted in a very bad outbreak of Salmon 
disease. Several times whilst we were fishing for trout on the 
“cours” great Salmon would come past in a dying state, at one 
moment swimming feebly and the next rolling over and over like a 
log. fine fish of 12 lbs. and upwards leprous with the fungoid 
growth which almost covered their bodies and was now choking 
them by invading the gills. It was quite piteous to see the fish in 
such a state. The disease did not appear to have communicated 
itself to the trout, probably because they would be moving about in 
all parts of the river and thus keeping themselves fit and clean. 
After a week or so abundant rain fell and there was a strong “ fresh ” 
in the river and it is to be hoped that many of the diseased Salmon, 
which were not too far gone, were able to get to the sea and there 
heal themselves of their grievous malady 
It may be interesting to those who are not aware of the fact to 
know that Salmon disease is caused by a microscopic fungus—a 
mould which belongs to the genus Sapolegnia, which in its turn is 
related to Peronospora. ‘There can be little doubt that the Salmon 
fungus is one of the moulds which grow so readily on the dead bodies 
of insects and are known to even invade their tissues in life. 
