li LABOEATORT BACTEKIOLOGY. 



EXEECISE VIII. 



THE INFLUENCE OF LI3IE AND MAGNESIA ON THE AMMONIFI- 

 CATION OF DRIED BLOOD AND COTTONSEED MEAL. 



1. Weigh ofE twelve 100 gram portions of air-dry, sieA'ed 

 soil, in tumblers. 



5. Arrange thus : 



1 & 2 — .5 grams dried blood. 

 3 & 4 — 5 grams dried blood + 1 gram OaCOj. 

 5 & 6 — 5 grams dried blood + 1 gram MgCO.. 

 7 & 8 — 5 grams cottonseed meal. 

 9 & 10 — 5 grams cottonseed meal + 1 gram CaCOj, 

 11 & 12 — 5 grams cottonseed meal + 1 gram MgOOj. 



3. Stir thoroughly with a startle spatula. 



4. To each add 10 cc. of a soil infusion prepared by 

 shaking 100 grams of a fresh sample of soil in 200 cc. of 

 sterile water for 5 minutes. 



.5. Add sterile water to bring the moisture content up to 

 the optimum for the soil and then 12 cc. additional for the 

 nitrogenous materials. 



6. Cover and incubate 7-8 days at 30° C. 



7. Then determine the ammonia formed by transferring 

 and distilling in the usual way. 



