1895.J MICROSCOPICAL JOURNAL. 301 



All know how constantly the glands are called into re- 

 quisition, the salivary glands for saliva, those of the 

 stomach and pancreas for their digestive juices, etc. If 

 we take now the pancreas as an example, and that of a 

 living fasting animal is put under the microscope so 

 that its constituent cells can be observed, it will be seen 

 that they are clouded, their outlines and that of their 

 nuclei being very vague and indistinct. The ceJl is ap- 

 parently full of coarse grains. If now the animal is fed, 

 as the digestion proceeds the pancreas pours out its 

 juice. At the same time the granules and with them the 

 cloudiness gradually disappear, the cells become clear 

 and both they and their nuclei are sharply outlined. 

 That is, the substance which is to form the pancreatic 

 juice is stored in the cells in the form of granules during 

 the periods of rest and held until the digestive agent is 

 demanded, and if the demand is great all the granules 

 may be used up. But as soon as the demand ceases the 

 cells begin again their special vital action, and again the 

 granules begin to appear and increase in number until 

 finally the cells become so full that they are fully charged 

 and again ready to pour forth the digestive fluid. This 

 is a daily, almost an hourly process. Let us take another 

 examination in which there would almost appear an or- 

 ganic memory on the part of the gland cells. No doubt 

 all have seen the clear jelly-like masses surrounding the 

 eggs of frogs and salamanders. Whence comes this 

 jelly that is so resistant to the agents that work so 

 quickly the destruction of ordinary organic matter? As 

 spring advances the cells of the oviduct increase enor- 

 mously in size. The microscope shows this increase to 

 be due to a multitude of clear granules. As the eggs 

 move along, the ova are coated with the jelly formed 

 from the granules given out by by tlie cells. As this 

 material for the jelly is poured out the cells gradually 



