SEA-FISHERIES LABORATORY. 289 



of connective tissue crowded with small, round leucocytes and 

 containing an abundant blood supply. That is all that can 

 sometimes be found. In other sections, however, even when 

 the surface of the skin is not eroded, but where there is only 

 inflammation, the presence of micro-organisms can be seen. 

 There are apparent spaces in the sub-dermal or dermal tissues 

 filled with small bacilli, very evident when the section has been 

 stained only with carbol fuchsin. Except for these, and a richer 

 blood supply than ordinary, there may be no evidence of a 

 pathogenic condition. In other cases there are plenty of 

 bacilli lying among the leucocytes in the marginal parts of the 

 sores, even although none may be found in the pus in the 

 central parts. Evidently, then, we have to deal with infections 

 — the ulcers may be regarded as generally septic ones in spite 

 of the condition that, in some cases, the micro-organisms are 

 difficult to detect. There was no opportunity for making 

 cultures, or for studying the living fish. This kind of investi- 

 gation demands an amount of time and special training which 

 we are, as yet, unable to give to the work. The only special 

 tests that were made were those for acid-fast bacilli, and in no 

 case were such successful. 



The interest of these specimens of ulcerated cod and other 

 fishes was increased because of various circumstances. The 

 number of diseased fish occurring in the North Sea arrested 

 attention during the last winter. Thus : " The skippers report 

 that they have never known such a year as the present one for 

 poorness in the quality of fish and the number of fish seen with 

 sores. They report that the sea is extremely dirty at all 

 places. It may be of interest to you to know that the herrings 

 landed this season at Yarmouth are all of very poor quality, 

 having the appearance of being starved." Again , " The general 

 condition of the cod caught in the deep water has been extra nely 

 poor. The majority of the fish are poorly furnished and are 

 termed ' slinks '." 



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