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190 REPORT OF THE COMMISSIONERS OF FISHERIES, GAME AND FORESTS. 



Description of tf)e Photographic Plates. 



The photographs represented in the following plates were made by Dr. Edward L. Learning, 

 of the Department of Pathology, Columbia University, New York: 



Plate I. A diseased trout, showing loss of the lower jaw bones. The lower figure represents 

 a gill from an adult fish covered with the parasitic Copepod Tracheliastcs. Photograph 

 magnified one and one-half diameters. 



Plate II. Two diseased trout, showing ulcers in the body wall. The testis is seen protruding 

 through the anterior hole in the lower fish. Magnified one and one-quarter diameters. 



Plate III. A group of spores of the parasite Lymphosporidium truttcR from the intestine. Some 

 rod-bacilli are seen near the center. Microphotograph, x 2000 diameters. 



Plate IV. Section of the testis to show the degree of infection. The black granular parts are 

 groups of spores of the parasite, the light parts are the epithelial tissues of the testis from 

 which the stain has been entirely extracted. Attention is directed also to the layer of 

 spores around the left margin of the section. Microphotograph, x 80 diameters. 



Plate V. A group of spores in the lymph surrounding the liver. Microphotograph, x 2000 

 diameters. 



Plate VI. A group of spores in the lymph surrounding the kidney. Microphotograph, x 2000 

 diameters. 



Plate VII. A group of spores from the body cavity and in the lymph surrounding the 

 intestine. Microphotograph, x 2000 diameters. 



Plate VIII. Spores in the lymph spaces between the muscles of the body wall. Micro- 

 photograph of a section from an ulcerated spot, x 2000 diameters. 



