247 
of Edinburgh, Session 1878 - 79 . 
mould exactly similar to that produced upon a solution of gum- 
arabic, gelatine, and meat infusions. I have tried to propagate the 
Saprolegnia fungus upon minnows, but without success hitherto, 
doubtless because the method adopted did not provide the proper 
means, there being awanting the necessary stimulus which exists in 
the river, or, what is more likely, the life of the fungus itself. The 
minnows were placed in a large glass vessel filled with town water 
from the tap. A piece of skin with this fungus adhering to it was 
taken from a salmon smolt and placed in the water along with them. 
In three days they had eaten up both skin and fungus, and remained 
unaffected. Several large patches of this fungus were then taken 
from the skin of a salmon and placed in the vessel along with them. 
In a few days it had all disappeared, and produced no effect. Another 
method was suggested by Mr G. H. List, who also kindly furnished 
me with material for the trial. Pieces of skin with this fungus 
growing upon them were cut from the bodies of dead salmon at the 
river side, and were put into wide-mouthed bottles, which were at 
once filled with river water, the skin not being allowed to dry. 
On receipt of the bottles the pieces of skin, along with the water in 
which they were brought, were emptied into the vessel among the 
minnows. The water in the vessel was not changed for three days, 
at the end of which time the minnows were still unaffected. Presh 
water was then put in the vessel, and the pieces of skin retained in 
the water, which was changed every second day for eight days. 
The minnows were not disturbed by the pieces of skin. They 
nestled under them and nibbled every morsel of fungus from them, 
hiding and playing about them until they had to be removed from 
putridity. All the minnows are still alive and are in beautiful 
condition, taking food greedily, worms cut small and crystals of 
sugar being their favourites. They have been kept since 14th May 
till now, 12th July, and are as healthy and lively as when put in 
the vessel. 
I have received from Thomas Key, Esq., Fellow of this Society, 
some information respecting a disease affecting the salmon in Lewis 
some years ago, which, from the sores of the skin of the head, 
resembled at a first glance a condition not unfrequently found on 
salmon affected with Saprolegnia. After examining my specimens, 
Mr Key wrote to me the following account of the disease in the 
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VOL. x. 
