TRANSFORMATION" OP AMMONIA NITROGEN. 41 



GROUP IV. THE CHANGE OF SIMPLE INTO 

 MORE COMPLEX COMPOUNDS. 



Exercises XXX. to XXXI. 



EXEECISE XXX. 



THE TRANSFORMATION OF AMMONIA NITROGEN INTO PROTEIN. 



1. Measure off eight 100 cc. portions of "Ammonia Nitro- 

 gen Transformation" solution into Erlenmeyer flasks. 



2. Plug and sterilize in the autoclave. 



3. Inoculate thus : 



1 & 2 — 1 cc. vigorous culture of B. vulgaris. 



3 & 4 — 1 cc. vigorous culture of B. mlrabilis. 



5 & 6 — 20 cc. (= 10 gm. soil) filtered, 5-minute infusion Soil 1. 



7 & 8 — 20 cc. (=10 gm. soil) filtered, 5-minute infusion Soil 2. 



4. Soils 1 and 2 should be of different types. 



5. Incubate 10-14 days at 20° C. 



6. Then add basic lead acetate to precipitate the protein. 



7. Filter, wash, and digest the residue by the regular 

 Kjeldahl method for total N. 



8. The results obtained show the power of the pure cul- 

 tures and the soils to transform ammonia nitrogen into 

 protein. 



