196 ON THE SAPROLEGNIE^. 



tended to the production of a weaker and physically degenerated 

 race. The coincidence should be borne in mind, that in all the 

 great instances of devastating fungoid disease, there has been an 

 undoubtedly weakened constitution in the subject, caused by over- 

 cultivation and in-breeding, preliminary to the attacks. Such was 

 the case with the silkworm, and it fell a prey to Botrytis ; with the 

 potato, and it succumbed to the Peronospora ; with the vine, and it 

 became a victim to Oidium; may we not add, also, with the 

 salmon ere it was devastated by Saprolegnia ? 



We cannot deny that artificial arrangements for the control of 

 nature inevitably fail. We make war upon small birds, and then 

 exhibit surprise that the insects make war upon us, or upon our 

 fields and orchards. We exterminate all the destroyers of sickly 

 salmon, and then express surprise that we rear a sickly race. The 

 argument was placed in a strong light when compared with the 

 grouse disease by a writer in " Land and Water." He says : — 

 " Take the case of the red grouse on our moors. The birds are 

 protected by law for the greater part of the year, and their natural 

 enemies, the various raptorial birds, are so assiduously hunted 

 down as to have become, in some cases, practically extinct in this 

 country ; and the consequence of this destruction of their natu- 

 ral enemies has been, that all the weakly birds, which in natural 

 circumstances would have been picked off by the larger hawks, 

 have remained to breed and perpetuate a still weaker progeny. 

 In a race of birds thus weakened, the parasite found everything to 

 favour its propagation, and the grouse disease became an epi- 

 demic ; and many proprietors, recognising this, are now protecting 

 the peregrine falcons as strictly as they preserve the grouse. 



" Something very similar has taken place with the salmon. 

 The otter is the natural enemy of the salmon in the fresh waters, 

 but they have been hunted, trapped, and shot, till not one re- 

 mains, where formerly there were dozens. The otter, like the 

 peregrine, takes the prey most easily captured, thus removing the 

 weakly, the sick, and in fact all those which, from whatever cause, 

 would give rise to a degeneration of breed. If there had been 

 otters in the district, in the numbers in which they once were, those 

 wretched-looking salmon now so frequently seen along the sides 

 of the Nith, would all have been dragged out and eaten by them. I 



