126 LABORATORY GUIDE IN BACTERIOLOGY 



13. Boil 2 minutes over free flame, constantly stirring. 



14. Make up loss by evaporation. 



15. Filter through absorbent cotton and cotton flannel, passing the filtrate 



through the filter until clear. 



1 6. Titrate and record final reaction. 



17. Tube, using 10 c.c. in each tube in the case of gelatin and agar. 



1 8. Sterilize 5 minutes in the autoclav at 120, or for 30 minutes in streaming 



steam on 3 successive days. Put at once into ice- water till solidified. 



19. Store in the ice-chest in a moist atmosphere to prevent evaporation. 



Blood-serum 



i. Fresh ox blood collected in sterile jars (museum jars) 



FIG. 37 

 Koch Inspissator 



is set in the ice-chest until the serum has separated. The 

 serum is filtered if necessary. 



2. Take 3 parts of this freshly prepared serum and i part 

 of, broth containing 1.5 per cent, glucose, and mix. 



