26 



treatment of the pancreatic tissue by strong alcohol does 

 not, however, seem to interfere with the action of the other 

 ferments. The digestive extracts may be prepared in differ- 

 ent ways according to the ability of the extractive medium 

 to dissolve the ferments. The ferments of the pancreas 

 differ from those of the stomach, in that they can act only 

 in an alkaline medium and not in the presence of acid. 

 The pancreas should not be prepared immediately after 

 death as the ferments are still in the form of zymogen gran- 

 ules. After remaining a few hours in a warm temperature 

 the zymogen splits up into the various ferments. As the 

 pancreatic juice is of an alkaline reaction, it affords an ex- 

 cellent medium for the growth of bacteria, and some anti- 

 septic must be used if the extract is to be kept for any length 

 of time. A few drops of alcoholic solution of thymol has 

 proven ver}' satisfactory. 



112. Aqueous extract. Divest the pancreas of as much 

 fat as possible. Mince it thoroughly or rub it well in a mor- 

 tar with well- washed sand or bird gravel. Add cold water, 

 stir and let the mixture stand for some hours. Strain 

 through muslin and then filter through paper. A more 

 powerful extract may be prepared by using a i % or 2 ^ so- 

 lution of sodium carbonate in place of the water, digesting 

 at 40° C. and adding a little 10% alcoholic solution of 

 thymol to prevent putrefaction. 



113. Glycerine extract. This may be made .similarly to 

 the glycerine extract of the gastric mucosa (99). After the 

 pancreas has remained at the laboratory temperature for 

 24 hours, it is usually placed in strong alcohol for a day or 

 two to remove the water and it is then put into glycerine 

 for some days. Filter, and in experiments use 20-30 drops 

 of the extract to 5 or 6 cc. of 1% sodium carbonate with 

 the material to be digested. Gamgee states that all of the 

 pancreatic enzymes are extracted from the gland bv glycerine. 



114. Brine extract. The fre.sh pancreatic tissue -is minced 



