Parasites, Diseases and Enemies. 255 



worms in their flesh. Dr. Leidy described this worm 

 under the name of Dibothrium cordiceps. 



CHAPTER XXXV. 



I 



DISkASES. 



English fishculturists, anglers and anatomists are 

 greatly troubled^by what they call the "salmon dis- 

 ease." Prof. Huxley said of it : "At first small whitish 

 patches appear on the skin. The smooth integument of 

 the top of the head, or of the end of the snout, is a very 

 usual locality, but the adipose fin and the axillse of the 

 paired fins are also among the first parts to be affected. 

 If there is an abraded or wounded surface, the disease 

 is pretty sure to attack it, but the invasion of the mal- 

 ady is in nowise dependent upon the pre-existence of 

 an injury. ... In the scaleless parts of the skin, 

 sloughing soon sets in and deep buri-owing sores are 

 formed. ... If the fluffy, whitish coat which is so 

 characteristic of the diseased skin — and is sometimes 

 tenacious enough to be stripped off in flakes like wet 

 paper — is examined microscopically, it is seen to con- 

 sist chiefly of a tangled mass of fine filaments on an 

 average about 1-2,000 of an inch in diameter, which 

 are at once recognizable as the stems (or hyphje, as 

 they are technically called) of a fungus, Saprolegnia 

 ferax, similar to those known as moulds." 



Prof. Huxley further says : "These observations 

 left no doubt in my mind that the Saprolegnia is the 



