30 



reproduced very rapidly, and may be cultivated on the 

 bodies of ordinary flies. The specimens I have examined 

 were thus cultivated from masses supplied through the 

 kindness of Mr. Murray of the British Museum. My object 

 being to describe the fungus and its life history, and not 

 to discuss the question of its relation to the disease itself, 

 as my results confirm those published by Prof Huxley in 

 a recent number of the Quart. Journ. Microscop. Soc, I 

 may pass over my disappointment at being unable to show 

 specimens of diseased salmon at this time of the year. 



Contact of the diseased salmon with a dead fly in fresh 

 water for 24 hours or less results in infection of the latter, 

 and very fine silky filaments are soon observed to shoot 

 forth in all directions from the body of the fly into the 

 water. If proper precautions are taken, the silky filaments 

 soon form multitudes of reproductive bodies, by which new 

 flies may be infected. 



The filaments radiating out from the body of the fly are 

 thin tubes with very delicate cellulose walls and coarsely 

 granular watery protoplasm. They branch both outside 

 and inside the matrix, thus extending the fungus, somewhat 

 as a bamboo is spread beneath the surface of the earth by 

 means of stolons, and a fig-tree, outside, by means of aerial 

 roots. 



After attaining a certain degree of development, the end 

 of an external branch swells up into a club-shaped body, 

 which becomes separated off" by a septum from the rest of 

 the tube : the protoplasm in this club-shaped " zoo-sporan- 

 gium" then becomes cut up into numerous minute " zoo- 

 spores," which remain for a short time closely packed in the 

 case like small shot in a cartridge. Suddenly, however, the 



