APPENDIX. 



121 



TABLE SHOWING ANALOGY BETWEEN BROTH, NUTRIENT GELATIN, AND 

 NUTRIENT AGAR MADE BY METHODS HEREIN RECOMMENDED. 



in 



Boil 30 gm. thread agar 

 i liter of water for half 

 -^ hour. Make up to a 

 weight of 1000 gm. 



Cool and solidify. 



NUTRIENT BROTH. 



NUTRIENT GELATIN. 



NUTRIENT AGAR. 



1. Infuse lean meat 20 

 hours with twice its weight 

 of distilled water in refrig- 

 erator. 



Say 1000 gm. meat. 

 ' 2000 " water. 



2. Make up weight of 

 meat infusion (and meat) 

 to original weight by add- 

 ing water, i.e. to 3000 gm. 



3. Filter infusion through 

 cloth to remove meat. 



4. Titrate and record re- 

 action of nitrate. Say 

 action + 2. 2%. 



5. Weigh infusion. 

 1800 gm. 



Say 



6. Set infusion on water- 

 bath, keeping temperature 

 below 60 C. 



7. Add peptone, i%, 18 

 gm. 



8. After ingredients are 

 dissolved, titrate, reaction 

 probably + 2.3 to +2.5. 



9. Neutralize, F u 1 1 e r's 

 method. 



Ditto. 



Ditto. 



Ditto. 



Ditto. 



Ditto. 



Ditto. 



Ditto and sheet 

 gelatin 10%, 180 

 gm. 



Ditto. 



Probably + 4.0 to 

 + 0.5. 



Ditto. 



Infuse Jean meat 20 hours 

 with its own weight of dis- 

 tilled water in refrigerator. 



Say 1000 gm. meat. 

 " 1000 gm. water. 



Ditto. 



i.e. to 2000 gm. 



Ditto. 



Ditto. 



Say reaction + 4. 2%. 



Ditto. 



Say 900 gm. 



Ditto. 



Add peptone, 2%, 18 gm. 



Ditto. 



Prob. +4-5 to +4.7. 



Ditto. 



To the 900 gm. of meat 

 infusion (containing now 

 peptone and salt) add 900 

 gm. of the 3% agar jelly 

 described at the head of 

 this column. 



10. Heat over boiling water (or steam) bath thirty minutes. 



it. Restore weight lost by evaporation to original weight of filtered meat 

 infusion, i.e. that on which the percentage of peptone and salt, etc., were cal- 

 culated, 1800 gm. in each case. 



12. Titrate, reaction probably +0.3 to +0.5. 



13. Adjust reaction to final point desired, + 1.5 per cent. 



14. Boil five minutes over free flame, with stirring. 



15. Add water, if necessary, to make up loss by evaporation, to 1800 gm. 



1 6. Filter through absorbent cotton, passing the filtrate through the filter 

 repeatedly until clear. 



17. Titrate to determine whether or not the desired reaction has been main- 

 tained. 



1 8. Tube and sterilize. 



