71 



ogonium. These are called "resting spores " because they do not die for some EDINBURGH, 

 time. They are emitted and rest. Cannot say' what they fasten on. When — 



they settle, and the plants grow, then the plague commences. 



The Saprolegnia ferax has been known many years. It is present, he thinks, 

 in all waters, at all times. 



Cannot speak as to the temperature favourable to its growth. Botanists say 

 there is a climatic influence of which they are ignorant. It is equally present 

 in both pure and impure water. It is not proved if impurities are favourable to 

 its growth. 



The resting spores of the fungus may be in abeyance for an indefinite time, 

 and propagate under certain climatic influences. They might rest for many 

 years, and in a year like this, when the hawthorn was everywhere in blossom, 

 the fungus might produce thousands of plants with zoospores ; the oospores 

 may have rested, and at last spread under peculiar circumstances. 



First saw it in the Tweed in 1878 and in the winter of 18/9. The 

 winters of those two years were very different from each other. Perhaps the 

 number of oospores was not plentiful enough to reproduce the Saprolegnia 

 ferax, although the peculiar circumstances may have existed in 1877- 



The sporadic cases of fungus on unclean fish, similar in appearance to the 

 Saprolegnia ferax, were perhaps the same fungus. 



r The new fact is that the clean fish have been affected. The action exerted by 

 the fungus on the fish is mechanical. The number of small fish affected 

 in the Eden was hardly 150 of big fish. The spores lighted on the big fish 

 easiest. The head being without scales is usually first attacked. A kelt 

 in a slimy state would hardly be more favourable for their growth than any 

 other fish. Has seen specimens from fish slightly as well as seriously affected. 

 The first symptom is a small spot, quite invisible till it has grown for hours. 

 To the naked eye it would be a white scurfy spot. Under the microscope 

 it is seen to be covered with filaments which cannot be seen by the naked eye. 

 They grow into long hair-like filaments. Made a cord from the fungus and tied 

 up a roll of paper with it. It held the papers for a day, but broke when dry. 



The fungus absorbs the mucus and eat3 through the skin. It continues 

 to grow until a counteracting influence appears. 



Sir Robert Christison sent him a grayling from the Nith. In one day the 

 fungus grew all over the fish. It grows on dead fish. It kills fish by hiding 

 the light, preventing endosmose and exosmose at the skin, and by suffocation. 



Has seen many cases of fungus inside the mouth. The attack in the mouth 

 is more deadly. 



At first thought the affected fish might be in a condition predisposing to 

 attack, but after observation does not think there is any functional predisposi- 

 tion to the fungus disease. All kinds of fish and in all conditions are liable 

 to it. 



It adheres more readily where there are no scales. 



Thinks the fungus is the same on both clean and unclean fish. 



The action of fungus is mechanical. The attack of fever in human beings 

 is zymotic. It is purely cutaneous. The fish might contract the disease by 

 contact, but the fungus is matted with mucous, hair, sand, diatoms, and all 

 kinds of rubbish. 



Cannot say why the disease is confined to the Border rivers. A climatic 

 influence might have existed specially there. 



The seeds might be carried by buds. Ducks in the spring, wading among 

 the fungus, might carry it away. It is no objection that the birds have carried 

 it to certain rivers only. It is possible that the disease, being stimulated in 

 one place, might be carried to others by birds. It is not probable however. 

 [Specimen produced of fungousy fish from the Usk.'] 



The wound on the right pectoral fin is like a wound from fungus. Its head 

 resembles the head of a fish from which he removed the fungus. 



Cannot explain why only the kelts have been attacked in the Usk, and not the 

 clean fish. 



All rivers are liable to be attacked. 



Salt is stated to have cured it. Cannot say if salt would kill the fungus. 

 Has fungus preserved in salt, which shows the same appearance as before it 

 was put in. Could only dissolve it in aquafortis. 



