226 Flow to obtain it. 
pining for their liberty, get into a morbid condition that renders 
them peculiarly liable to attacks of fungus. 
I think I may safely say that I could cause fish to be attacked 
with fungus by simply placing them in a wooden tank, or in a 
newly-made one of concrete. I have done so, and have then 
removed and cured them. One very interesting and important 
feature I have noticed, and that is that a fish that was not itself 
attacked by fungus, on being removed transmitted it to others. 
I have taken fish that have been affected, as in case No. 3, and 
have destroyed every scrap of fungus upon them. In a few days 
a fresh crop has been found growing, and the fish has been put 
under treatment again, and again a third, and perhaps a fourth 
time. If taken during an early stage of growth, four out of five of 
such fish are curable. 
The average life of a trout is about ten years. When dying 
of old age they are largely attacked by fungus, which kills them. 
On a fish farm they are not allowed to die of old age, but are 
killed and marketed before that time comes. I had rather an 
interesting case a few years ago. A Buttermere trout, which I 
had kept by way of experiment, died, at the age of over seventeen 
years. When in its prime it turned the scale at six pounds and 
three-quarters, but at the time of its decease it had become long 
and lanky, and weighed under five pounds. It was attacked by 
fungus, which was removed by means of a saline bath and the use 
of carbolic about a dozen times in as many weeks. The fish then 
succumbed. Its allotted time had come. This happens to most 
fish that are not caught, and the use of fungus seems to be to 
destroy not only the lives of these old fish, but to live on their 
bodies also, and it fulfils its mission. They are its legitimate prey, 
and are designed by Nature to be so. 
In all cases of fungus on fish that have come under my 
notice, I think I may safely say that there has been a predisposing 
cause. Either old age, a morbid condition, wounds, removal of 
the mucous coating, or something else, has been underlying the 
attack. To preserve our fish from this deadly enemy as far as 
possible, our aim must be to keep them in health. If we allow 
them to deteriorate, and to assume a low state of vitality, we give 
the fungus a better chance. A great deal more depends upon the 
