A. 



38 



the extract. Fill B half full of 0.2% hydrochloric acid. 

 Treat C similarly to B, but add 30 drops of the extract. Fill 

 D half full of a 1% solution of sodium carbonate and add 30 

 drops of the extract. Place 30 drops of the extract in E and 

 add 2 or 3 cc. of distilled water and boil, then add enough 

 0.2% hydrochloric acid to make the tube half full. In F put 

 2 cc. of the extract and 2 cc. of bile and fill the tube half full 

 of 0.2% hydrochloric acid. In each of the 6 test tubes put a 

 small thread of well-washed and boiled fibrin. Place all the 

 tubes in a water bath at 40° C, and after an hour note any 

 changes that may have occurred in any of the tubes. The 

 rapidity of action will indicate the strength of the ferment. 

 Explain in your notes why no action has occurred in certain 

 of the tubes. Test-tube C is to be plugged with cotton and 

 reserved for later examination, in the next exercise. 



122. The following tubes are to be prepared exactly as C 

 but omitting the fibrin. In the first tube a very small piece 

 of meat ; in the second a crumb of "bread; in the third a bit of 

 boiled potato ; in the fourth a small piece of dried albumin ; 

 in the fifth add a small piece of butter ; in the sixth, 1 cc. of 

 milk diluted with 5 cc. of distilled water ; in the seventh test- 

 tube a small piece of gelatin ; in the eighth tube small 

 amounts of all the above substances. These tubes, also, are 

 to remain in the water bath at 40° C, and tested later for 

 intermediate and end products. (See 124, 125, 127). 



IX 



123. The contents of tube C is- to be divided into 4 parts, 

 3 of which are to be used in the following tests, and the other 

 part to be held in reserve, if needed, to correct any of the 

 other tests. 



124. Color one portion of the fluid with the litmus solu- 

 tion and neutralize by the contact method with 1% sodium 

 carbonate. (See plate I). At the neutral zone a precipitate 

 will appear indicating acid- albumin (syntonin). The contact 



■ test'Mthout tl^litmus is equally delicate. 



125. Add to another portion of the s3ution enough crys- 

 tals of neutral ammonium sulphate to saturate it. This brings 



