of Edinburgh, Session 1878-79. 
245 
fish ; in one hour the cilia will have disappeared and a filament of 
some length will have sprouted from the spore. Thus, in a single 
day, a fish, on which no fungus could be discerned, is to-morrow 
seen to be affected, and in three days is spotted or patched over 
with fungus from head to tail. 
In the second or sexual mode of production of spores a short 
pedicle is pushed out from one of the sides of a filament on which 
a globular sac — oogonium — is formed, and within this sac a num- 
ber of oospores are produced, which are spherical in shape and 
have a cell wall or envelope, and some are provided with a nucleus 
in the centre. These, after impregnation, escape from the oogonia, 
and are probably capable of living in the water for an indefinite 
period, in a dormant or resting state, until the conditions arise 
which are favourable for their germination. 
It may be asked, how does the fungus affect the fish, and do any 
recover from its effects ? The fungus produces a local irritation and 
inflammation of the integument, as is evidenced by the conges- 
tion, and even ecchymosis of the true skin, by abrading of the 
scales, and in the more advanced stages by ulceration and slough- 
ing, affecting the whole thickness of the integument and mucous 
surface. 
Wherever the fungus adheres and spreads, the function of the 
skin is necessarily interfered with. Light, which is so essential to 
the fish in promoting its pigmentary secretions, is cut off from a 
large portion of its skin. Endosmosis, exosmosis, and the secretion 
of the mucus for lubrication are destroyed, and in this way con- 
stitutional symptoms would be occasioned which, if the disease 
continued, lead to the death of the fish. 
The second question, Do any fish recover from fungus attack ? 
may now be answered more hopefully. The fishermen and watch- 
men on the Tweed report having seen several fish with new skin 
growing over the sores upon their bodies, from which this fungus 
had disappeared, and I am inclined to believe that this is so. A 
male kelt has been sent to me by Mr List, which was taken in tidal 
water below Eerwick bridge. This fish is 2 feet in length, and weighs 
about three or four pounds ; it is supposed to have been affected 
with fungus, and to have completely recovered from its effects. No 
particle of fungus could be found upon any part of its body, and 
