SEA-FISHERIES L.ABOEATORY. 161 



It lias been suggested that these lesions are due to 

 accidental injuries received either in the trawl or in the 

 storage pond. While it is not impossible that such 

 injuries may be a slight contributing factor, we cannot 

 regard them as the cause. If they were, it would be very 

 difficult to account for the absence of disease prior to 

 1905, though the conditions of capture and storage have 

 undergone no change since that year. 



Taking all the evidence into consideration we 

 believe, though we do not consider it definitely proved as 

 yet, that this disease is bacterial and probably connected 

 with one of the three bacilli which we have described. 

 The condition is, then, a septicaemia strictly comparable 

 to those described by Anderson and Ceresole. All the 

 evidence appears to us to point to this conclusion. 



EXPLANATION OF THE PLATES. 



Plate I. 



Fig. 1. — Head of diseased Plaice showing ulceration. 

 Fig. 2. — Another specimen showing ulceration at 

 base of dorsal fin. 



Plate II. 



Fig. 1. — Smear from an ulcer of Fish I, showing the 

 Bacilli. From a micro-photograph. 



Fig. 2. — Smear from liver of Fish I. From a 

 micro-photograph . 



Fig. 3.- — Blood-smear from Fish I. From a micro- 

 photograph. 



