Alga and Faitga.s in Saijnoii JJise<is(\ 29 



more enfeebled until death ensued. Brown and Lochleven fry 

 were also affected, but not to the same extent. On many of 

 the tish there appeared tufts of vegetable growth siuLilar to 

 those noted by myself in Victoria, and by Minakata in Japan, 

 the branched filaments of M i/ roncnut being about 1 cm. long 

 and attached to almost any part of the body, but mostly to 

 back and sides. Tlie fungus previously referred to was present, 

 and I am satisfied that it is at least a member of the Sapro- 

 legniaceae, if not a species of Saprolegnia. Amongst the fila- 

 ments of these composite tufts there were other algae, both 

 multicellular and single-celled plants, some of the latter being 

 motile. 



While numy of the weak and dying tish bore no conspicuous 

 growth, and showed on closer examination no fungus mycelium, 

 they were still in a diseased condition, disorganisation of the 

 mouth parts, gills, fins and other portions of the body being 

 easily seen, the scales having been lost from the affected areas. 



Sometimes the Saprnhgnia appeared alone, but usually, if 

 not always, at spots where ulcerations were in evidence. I was 

 unable to find any attached M yroiiema apart from the fungus. 

 It is possible that in the case quoted by Harz^ not necessarily 

 an enzyme, but probably a bacillus prepared the way for the 

 fungus mycelium. On the other hand, Professor Huxley" iu 

 sisted that this view of SaproJegnia, which marked it as a 

 Saprophyte, was incorrect, and gave an account of experiments 

 by which he was able to demonstrate the gradual encroach- 

 ment of the mycelium threads, from an infected part, on sound 

 tissue of the epidermis, which they destroyed in their progress. 

 In view of the absence of visible fungus under ordinary micro- 

 scopic examination in present case, I put forward the sugges- 

 tion that a bacillus such as B. Kalvwnia pestis^ or B. piscicidus 

 hipolaris* prepares the tissue for the Saprohgnia, which is 

 then a Saprophyte, but that it may in the absence of such a 

 bacillus adapt itself to other conditions, and then as a true 

 parasite dissolve the tissues for itself by means of an enzyme. 



1 Jour. Roy. Micr. Soc, 1907, p. 201. 



■1 Report, Fisheries Exhibition [jitcrature, vol. vi., 1882. 



3 Rep. British Association, 1002. 



4 Proc. Linn. Soc. N.S. Wales, vol. xxv., 1!)00, pp. 1'22-130. 



