102 Swale Vincent and F. D. Thompson, On the Relations between etc. 



Fig. 14. Islet from pancreas of frog — same preparation as preceding. The islet 

 consists of clearly-marked columns of lightly staining cells with very wide 

 capillaries occupying the spaces between them. Compare this figure with 

 fig. 1 from the dog, and with the next figure (15) from the salamander. 

 X 500. Cam. lue. Reduced to ^/3 of the original size. 



Fig. 15. From the pancreas of Plethodon glutinosxis, showing the arrangement of 

 elongated cells around a large blood-vessel. See text. Flemming's fluid, 

 iron-haematoxylin. x 400. Cam. lue. Reduced ^/g. 



Fig. 16. From another part of the same preparation as the preceding. Shows 

 leptochrome islets in the form of cells (in part or wholly leptochrome) 

 arranged round capillary blood-vessels, x 400. Cam. lue. Reduced to ^/j. 



Fig. 17. „Principal islet" of Ammrus nigricans, showing connective tissue septa 

 accompanied by strands of zymogenous tissue, and also portions of 

 zymogenous tissue distributed in the islet. Corrosive sublimate, haema- 

 toxylin and eosin. Cam. Inc. x 400. Reduced ^/2- 



Fig. 18. From the pancreas of Esox lucius. Shows transition between islet and 

 zymogenous tissue, also a separate mass of the latter enclosed in the 

 former. Corrosive sublimate, ha'ematoxylin and eosin. Cam. lue. x 400. 

 Reduced to ^/3. 



(The preceding investigation is part of the work of a Commitee of the British 

 Association for the Advancement of Science, to which a grant of money was made 

 by the Association.) 



