APPENDIX 
RECENT RESEARCH ON THE SALMON DISEASE 
Since the observations upon the salmon disease (pp. 210-212) 
were printed, Mr. J. Hume Patterson, Assistant Bacteriologist 
to the Corporation of Glasgow, has published an account 
of the important discovery he has made in the course of his 
researches into the nature of the disease.* His report contains 
a detailed description of the experiments whereby he has 
established the fact that the fungoid growth known as Sapro- 
legnia ferax does not constitute in itself, as Professor Huxley 
supposed, the active agent in the disease. Saprolegnia 1s 
simply a mould or fungus, which finds its appropriate soil 
in dead animal matter, and is no more capable of growing 
upon living flesh of fish than it is upon the surface of a 
flint. 
But Mr. Patterson has discovered a micro-organism which 
does establish itself in the bodies of living fish, especially 
those of the salmon kind. Apparently this micro-organism 
can only invade the body of the fish where the superficial 
tissues have been wounded; in other words, where the skin has 
been injured or broken. Having obtained entrance in this 
way, it multiplies with great rapidity, forming areas of necrosed 
or dead muscle, which offer a suitable nidus for the Saprolegnia. 
Mr. Patterson has named this new micro-organism Bacillus 
* The Cause of the Salmon Disease: A Bacteriological Investigation. 
By J. Hume Patterson. Presented to Parliament by command of His 
Majesty. Price ts. 2d. 
395 20 
