XXIIl] PANCKEAS AND LIVER 185 



clear unstained parts of the cells ; small brown stained 

 granules, and possibly some black fat globules, will also 

 be seen (cp. with 4, a). 



NOTES. 



Pancreas. 



Mercuric chloride may be used instead of alcohol for 

 hardening. 



Resting and Active gland. A mammal is killed 5 to 8 hours 

 after a full meal for the active gland, and one 12 to 16 hours 

 after a full meal for the resting gland. In the frog, the corre- 

 sponding times are 8 to 10 hours, and 1 to 2 days; the frogs 

 should be fed with worms ; in unhealthy frogs and in those 

 which have long fasted, the pancreas cells have usually a distinct 

 outer non-granular zone. . 



The pancreas of a rabbit may be taken to show in an injected 

 specimen the enlarged and close-set capillaries in the inter- 

 tubular clumps. 



Liver. 



Glycogen in liver. Give a rabbit a full meal of bran and 

 carrots ; in about six hours decapitate, and place small pieces of 

 the liver in hardening agents. 



Natural injection of bile ducts. Inject into a blood vessel of 

 an anaesthetized animal a saturated solution of sodium sulphin- 

 digotate (about 20 c.c. in a cat) ; repeat in hour and again in 

 an hour ; in about another hour and a half, kill, harden pieces 

 of the liver in absolute alcohol, stain in bulk in eosin in absolute 

 alcohol, cut in paraffin. 



The liver of the frog may be obtained with the tubes separated 

 from one another, by injecting salt solution through its blood 

 vessels (by way of the aorta for 5 to 10 minutes). The liver may 



