- SEA-FISHERJES LABORATORY. 197 



Although these nodules occurred singly for the most 

 part, there were patches of skin where they were grouped, 

 and here the lesion was a distinctly ramifying one, 

 sometimes even dendritic in appearance. This was more 

 particularly the case on one side of the fish, and on both 

 sides between the beginning of the third dorsal fin and 

 the root of the tail fin. In some places quite consider- 

 able areas of skin were involved. Over the nodular 

 lesions the epidermis had quite disappeared and there 

 were no traces of scales, but elsewhere the skin was 

 apparently normal in structure. On slicing away the 

 surface of these little nodular masses a cheesy-white 

 substance was disclosed, and sometimes this could be 

 apparently "shelled-out," when it appeared as little 

 granular masses of various shapes and sizes. Some of 

 these were stained and cleared up, but they showed no 

 obvious indications of structure. 



In my absence from the laboratory the fish was 

 preserved in formalin. It was first of all examined, as 

 above described, for the possible presence of worm 

 parasites, but nothing of the kind was found. Hough 

 smears were then made from the substance in the nodules, 

 to see if fungoid or protozoan organisms were present, 

 but again with negative results. Sections through the 

 nodules were then made, and were stained in various 

 ways, methyl-blue-eosin, iron-haematoxylin followed by 

 eosin, Ehrlich's haematoxylin and eosin, and Mallory's 

 stain. On examining the sections so prepared it was at 

 once seen that morbid tissue formation had taken place, 

 and what was seen indicated the presence of an infectious 

 granuloma of some kind. Prof. Glynn, of the Patho- 

 logical Department, to whom I showed the sections 

 and specimens, at once noticed their resemblance to 

 tuberculous lesions, and suggested staining for acid-fast 



