Transactions. 73 



by Camera Lucida) rougli drawings of some of the forms that I 

 have met with, although they by no means complete the variety. 

 I think the tubes or cells of the filaments are oval, not circular ; 

 at least, I am led to think so by the appearance presented. They 

 are generally built up of two, and sometimes of three, large cells. 

 Some of the filaments are filled with a protoplasmic-looking 

 substance. " That," says Mr Worthington Smith, the eminent 

 fungologist, " gradually changes to the granular form," which 

 indeed is the form most commonly met with ; and those granules, 

 which are the spores of the fungus, begin to have a motion of 

 their own inside the parent cell, and when the proper time comes 

 they are discharged by the sporangia at the apex of the filament. 

 After these filaments have dischai-ged part of their living freight, 

 those spores then take the form of Zoospores, " having two cilia," 

 moving about in the wuter like true Animalcuhe, ready to attach 

 themselves to any proper substance that may come in their way 

 on which to germinate, and throw out filaments similar to those 

 from which they came ; indeed, so prone are they to grow that it 

 has been supposed that filaments having the form represented in 

 the diagram are those in which the spores have actually germinated 

 in the parent cell. Now, when we look at the thousands of fila- 

 ments on one single spot of disease, and consider that each of 

 those filaments gives off a numberless quantity of spores, we will 

 begin to have some idea that the quantity of Zoospores lodged in 

 and floating down an affected river must be beyond all calculation. 

 One feature I noticed in connection with those Zoospores — that 

 if, when under observation, a stream of liqxxid was made to flow 

 across the slide, they could attach themselves to the glass, so that 

 tliey were not carried away by the stream, and by the same means 

 will attach themselves to the stones, &c., in the river, or the dorsal 

 fin of a Salmon. I have not been able to trace the roots of the 

 fungus beyond the skin that covers tlie scales. In making a cut 

 into the fish throvigh the fungus, the eye at once is attracted by an 

 inflamed, unhealthy-looking stratum of muscle below the skin, of 

 varying thickness. In one fish that I examined it extended right 

 tlirough to the inside. Sections of that muscle when placed 

 under the microscope wei'e seen to be litei-ally one mass of life — 

 that life being a species of Bacteria. If I am asked the question. 

 What are Bacteria 1 1 cannot answer it. Some philosophers call 

 them vegetable forms of life, and some seem to doubt it ; but this 

 I can say, tliat they are small, discoid-looking bodies, which in 



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