22 Investigations on the Life-History 



mucous membrane cut across and covered with columnar epithelium. 

 Hsematoxylin and eosin. 



Fig. 6. T.S. Intestine of salmon from upper waters, with catarrhal 

 change far advanced. Only a few patches of epithelium at the bottom 

 of the folds remain attached, and these are degenerated. Hseruatoxylin 

 and eosin. 



Fig. 7. Stomach of salmon from mouth of river, to show normal 

 arrangement. Hsematoxylin and eosin. 



Fig. 8. Superficial epithelium of stomach (estuary salmon). Irori- 

 hsematoxylin. 



Fig. 9. Junction of intermediate and zymin-secreting epithelium from 

 gastric gland (estuary salmon). Iron-hsematoxylin. 



Fig. 10. Stratum compactum from gastric mucous membrane (estuary 

 salmon), to show its continuity with the neighbouring connective 

 tissue-fibres, and the number of eosinophile leucocytes about it. (The 

 details of the nuclei of the leucocytes have been omitted). Hsernatoxy- 

 lin and eosin. 



Fig. 11. T.S. through whole thickness of wall of pyloric appendage 

 (estuary salmon), to show arrangement and the identity of its structure 

 with that of the intestine. Hsematoxylin and eosin. 



Fig. 12. Portion of a longitudinal section through a fold of intestinal 

 mucous membrane (estuary salmon). Haematoxylin and eosin. 



Fig. 13. Intestine of salmon from mouth of river, showing a patch of 

 normal epithelium at the bottom of one of the folds, and the process of 

 degeneration and desquarnation which the cells are undergoing. Hsema- 

 toxylin and eosin. 



Fig. 14. Pancreas (estuary salmon), showing its distribution in the 

 fat lying between the pyloric appendages. Hsematoxylin and eosin. 



Fig. 15. Pancreas (trout), showing an acinus in the "resting" stage, 

 with the cells full of zymogen granules. Iron-hajmatoxylin. 



Fig. 16. Pancreas (trout), showing an acinus in the "active" stage, 

 when most of the granules have been discharged. Iron-hsematoxylin. 



Fig. 17. Liver (salmon), from upper water, with only a small amount 

 of fat in the cells. Hsematoxylin and eosin. 



Fig. 18. Liver (salmon), from sea, the cells distended with fat 

 globules. Hasmatoxylin and eosin. 



