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DE-MC. called the " mushroom spawn." They serve the purposes of roots, attaching the 

 X300KE. fungus to the substance upon which it grows, sucking in moisture, and 

 spreading with enormous rapidity when the matrix is favourable. As these 

 root-fibres spread, they continue to send up new stems or filaments, and thus 

 as the root filaments spread in the juicy flesh, so does the tuft of fungus grow 

 larger and larger every hour, by the constant production of new threads, which 

 spring from the spreading roots. It need cause no surprise that, when one 

 spot has began to grow its fungus the progress is extremely rapid, and the 

 patches grow larger every hour. But it rn/iy be asked, how do they commence ? 

 Let me answer this somewhat suppositiously, from analogy of the process in 

 other fungi. The border rivers, for example, contain myriads of germs of this 

 fungus from previous years, which float in the water in search of some suitable 

 spot on which to grow. They will only grow on certain substances, and one 

 of these is the bruised or abraded flesh of the salmon. A fish having a bruised 

 spot no larger than a pin's head, affords a suitable locality, and the spore or 

 germ adheres to it, and begins to grow. The growing point at once 

 enters the wound or bruise, and, when once entered, it spreads in all directions 

 with rapidity. As soon as the mycelium, or fungus roots, are well established 

 the stems are produced and the first little tuft appears, two or three, then 

 twenty or thirty stems, and shortly a patch visible to the naked eye, and thus 

 the fungus commences upon each spot. Naturally enough the fungus makes 

 its appearance first on the fleshy parts of the fish, such as the head and tail. The 

 softest parts are most liable to have suffered injury, and the soft parts are those on 

 which the spores would attach themselves, and begin to germinate. The germi- 

 nating threads are delicate and would fail to penetrate the scaly parts. Probably 

 when the fungus does extend over the scaled parts of a fish it does so by the 

 spreading of the root threads, under the cuticle, from the older patches on the head 

 and fins. This, however, is conjecture. One fact is certain, the fungus always 

 commences upon the soft parts of the fish. There must be some cause for this 

 fact. This cause I believe to be that all external injuries to the fish are 

 inflicted on the exposed parts, and such injuries prepare the home for the 

 fungus ; and, moreover, there is no obstruction to the growth and development 

 of the germs in the naked parts. It is a difficult thing to demonstrate by 

 experiment whether the germs of the fungus will commence to grow upon 

 healthy unpunctured skin of a salmon, or, if they germinate, whether they 

 possess the power of perforating the skin. My own opinion is that they would 

 not. In plants the germs of the parasitic fungi commence growth on the 

 surface of the leaves, the extremities do not pierce the very delicate cuticle, 

 but enter by the stomata, or breathing pores. It is scarcely probable that 

 threads equally as small and delicate would penetrate the cuticle of a fish. 



When the threads of which this fungus is composed become fully matured 

 they produce fruit. I need not detail the process which terminates in the 

 upper parts of the threads being filled with minute bodies, nearly egg- 

 shaped, but exceedingly small, which escape by a perforation at the end. 

 These germs are called zoospores, each being furnished with a pair of delicate 

 hairs, endowed with active motion, and like a pair of oars propel it actively 

 through the water. Every tuft of fungus produces swarms of these active 

 moveable germs ready to attach themselves to any unlucky fish. If they do 

 not find the suitable spot on which to grow they never germinate at all. It 

 is altogether an error to suppose that they will grow upon any other sub- 

 stance than their natural pabulum, which is fish of almost any kind, fish ova, 

 the spawn of frogs and newts, and probably of some water snails. There is 

 also another kind of fruit which this fungus produces in little capsules, or 

 cells, terminating short side branches. These are the resting spores, which 

 fall off and sink to the bottom of the water and rest through the winter, 

 ready to burst and liberate the imprisoned germs, which each one contains, 

 in the early spring. Thus nature has provided against all the zoospores 

 being destroyed by a hard winter, and the fungus extirpated, by enclosing 

 from five to twenty in a thick tough skin or shell, which rests quietly in the 

 water until the return of spring." 



Fungoid Parasitism,. — The parasitism of fungi on plants is unfortunately but 

 too common, and the parasitism of fungi on animals is by no means rare. In 

 both instances this parasitism is of two distinct kinds. That of animals 

 concerns us most, in this inquiry, and we shall chiefly address ourselves to 



