SEA-FISHERIES LABORATORY. 207 



of this strong fibrous capsule, an ill-defined layer repre- 

 senting the nucleated tissue of fig. 1 and the central 

 capsule. . In many cases the body within the central 

 capsule has burst the latter and has begun to exhibit 

 vegetative reproduction. In figs. 2 and 3, PL I, such a 

 case is represented — doubtless the beginning of formation 

 of a mycelium. 



The tissues of the renal organ apart from these bodies 

 are quite normal. Several excretory tubules are repre- 

 sented in fig. 1 surrounded by small lymphocytes — all 

 this is perfectly normal, and the fixation of the tissue 

 is quite satisfactory. 



In a number of places both in the liver and renal 

 organ, " nests " of bodies exist, lying almost loosely in 

 the general renal or hepatic tissue. Such a " nest " is 

 shown in fig. 4, PI. I. It contains a number of small 

 spherical bodies, each surrounded by a rather delicate, 

 structureless capsule, and the whole lies quite loosely 

 among the liver parenchyma. In some cases these 

 capsules burst, and the contained body appears to be 

 proliferating or budding. This is shown in fig. 2, in 

 its first stage. In fig. 4 there is undoubtedly the 

 beginning of a mycelium, and this is still more clearly 

 shown in fig. 3, which represents part of a section of 

 the renal organ. We have clearly a case of the infection 

 of the fish by a fungus, and the growth of the latter 

 within the organs. 



Dr. H. M. Woodcock, to whom I showed these 



sections, has drawn my attention to a paper by Plehn 



and Mulsow,* in which the causes of the disease called 



" Taumelkrankheit," by Hofer, are investigated. This 



is a disease attacking fresh-water fishes, chiefly trout, 



* Plehn and Mulsow, " Der Erreger der ' Taumelkrankheit ' der 

 Salmonidea." Centralbl. f. Bakt. LIX Bd., 1911, Originale, pp. 63-68, 1 pi. 



