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any abraded surface, with which it may come in contact, in from 24 to 36 hours. 

 Mr. George Murray, of the Botanical Department of the British Museum (who 

 has been assisting Professor Huxley in his investigation of this subject), inoculated 

 two healthy dace on the 2nd March, 1883, with a diseased fly. On the 5th March 

 a patch of disease was visible, which had become much larger on the 10th March. 

 On IMarch IGth one fish died covered with fungus ; the other fish had escaped, but 

 was afterwards found dead just as extensively diseased. Under similar treat- 

 ment two others died ; one in 10 days, the other in 14 days. 



Saprolegnia ferax attacks any kind of fish, eels, frogs (it has been found 

 growing upon frog-spawn and upon the ova of fish), tadpoles, beetles, as well as 

 many other forms of organic matter. The disease is not confined to our own 

 rivers, for it has been observed in Russia and America. It is often very trouble- 

 some and fatal in the aquarium, and broke out in the Fisheries Exhibition a few 

 days after it was opened. 



When the Saprolegnia attacks a fish, a diseased patch or patches are observed 

 to appear first upon such soft parts of the fish as are devoid of scales : these 

 patches are ash-coloured, raised in the centre with a well-defined margin, from 

 which the disease extends with marvellous rapidity, neighbouring patches becom- 

 ing confluent, until the entire body— if the fish lives long enough— gets covered 

 with a gray gelatinous mass adherent to the skin. In the early stages the patches 

 can be removed, and the scales underneath are found undisturbed. In advanced 

 cases the disease is found extending beneath the scales and epidermis, which has 

 been destroyed, into the true skin. The fish now presents the appearance of being 

 covered with light gray or whitish patches, and in its latter stages the tissues of 

 the tail and fins are often eaten away, leaving the rays bare and separated. The 

 fungus, when it has appeared upon the soft integument of the head, extending 

 over it, closes the eyes, plugs the gill covers and the mouth, whence it often 

 extends along the mucous membrane ; sloughing and ulceration even to the very 

 bones of the head not unfrequently occurring. The unfortunate fish attacked must 

 suffer greatly from irritation, and apparently dies from exhaustion, and suffocation 

 due to obstruction of its respiratory functions. It does not lose much in flesh, 

 which may be attributed to the rapid growth of the fungus, causing a speedy fatal 

 termination, and, indeed, upon a careful examination, the body and viscera of 

 the fish are usually found healthy, the disease being confined to the skin itself. 

 In fact, there are found some martyrs to science, who, having ventured the experi- 

 ment of eating salmon thus diseased, are not only still surviving, but confess them- 

 selves to have been unable to detect any depreciation of the characteristic flavour 

 of the healthy salmon, or to have been in any manner affected by this food, whose 

 associations alone would repel any ordinary appetite, unless it were goaded on by 

 the cravings of hunger or of science. 



By the kind permission of Professor T. H. Huxley, I am allowed to make 

 any use I like of his diagram which accompanied the Twenty-first Annual Report 

 (Blue Book, C. 3127 of 1882) of the Inspectors of Salmon Fisheries for the year, 

 1881. A study of the figures will more impressively explain the character of the 

 Saprolegnia Fungus. To this Report, and also to the Report of Salmon disease in 



