of the Fishery Board for Scotland, 



381 



S. torulosa. A photograph of it may be seen in Plate IX. fig. 4. Here, in- 

 stead of the terminal portions of the hyphse being surmounted by a single 

 sporangium, we have a necklace-like arrangement of sporangia, some being 

 almost completely spherical, others broadly ovate, while others approach 

 the form found in S.ferax. 



Further, we find here the non-terminal sporangia in some cases throwing 

 out buds or branches into which the granular matter is continued. 



At an early period of my investigation I determined to attempt arti- 

 ficial pure cultivation on previously sterilized media. For this purpose 

 I had prepared small flasks containing a small quantity of finely 

 divided bread to which a small amount of water was added, sufficient 

 to make the mass coherent, and the flasks being then plugged with 

 cotton wool and efficiently sterilized by boiling in a steam sterilizer, 

 were on cooling ready for use. Portions of the fungus were then 

 removed from the fish by means of a platinum needle and inserted into the 

 flasks, which were then left for some days to await further results. 

 I have found, in the case of fungus derived from salmon, that it, when 

 pure, i.e., when not intermixed with bacteria and other fungi, grows 

 luxuriantly and forms masses exactly like pure cotton wool, forming- 

 masses which may almost fill the flask and of which the terminal parts 

 may be as much as two inches removed from the source of nutriment. 

 On examination, microscopically, I find the hyphse to be much narrower 

 (see Plate IX. fig. 2) than the fungus growing in water, and not so 

 far possessing sporangia. On the other hand, however, I have found, pre- 

 sent, though so far somewhat sparingly, bodies similar to oosporangia, 

 and which indeed I regard as such (see Plate IX. fig. 5). On taking such 

 a cultivation and placing it in water it is found that the hyphse rapidly 

 swell, becoming eventually in all respects identical with the fungus 

 found in the salmon, and developing terminal sporangia exactly similar 

 (see Plate IX. figs. 6, 7). 



I have attempted, with such cultivation, to infect minnows and gold- 

 fish, but without success. Although I may mention that one gold-fish, 

 which died without showing signs of it during life, developed a plentiful 

 growth immediately after death, I am not able to prove conclusively 

 that its infection was due to my inoculation. My reasons for this lies 

 in the peculiar fact that artificial cultivations of fungi, on bread material, 

 derived from salmon, minnow, and char each show to the naked eye 

 absolutely different appearances in their forms of growth, and this 

 conveys to me a slight suspicion of there possibly being different 

 varieties of Saprolegnia affecting different kinds of fish. In any case, if 

 Saprolegnia can grow in air in a laboratory, and still further develop 

 bodies similar to oospores, it follows that we may with perfect rig] it 

 infer that there is probably a terrestrial form of Saprolegnia, although 

 it has not yet been discovered. We may anticipate that careful investi- 

 gations carried out in this way may lead to an important accession of 

 knowledge. 



Description of Figures, which have been reproduced from Photo- 

 graphs TAKEN BY Mr EDINGTON. 



Fig. 1. Mycelium of cultivation on bread paste, derived from salmon 



fungus. x 45 diameter. 

 Fig. 2. A portion of the same, more highly magnified, showing the 



pseudo-dichotomous branching. x 80 diameter. 

 Fig. 3. Fungus growing on a char, showing sporangia of the common 



form, x 45 diameter. 



