AMMONIACAL FERMENTATION OF URINE 225 



(<r) Observe the urea fermenting colonies which are surrounded 

 with small white crystals of calcium carbonate. 



(d] Transfer portions of the different colonies into flasks of 

 the following nutrient medium suggested by Beijerinck : 

 Water . . ... . . 1000 c.c. 



Sodium acetate . . . . 10 gr. 



Mono-potassium phosphate 



(KH 2 P0 4 ) . 25 gr. 



Urea 50 gr. 



Incubate each at 22 or 30 C. 



Note and compare the production of ammonium carbonate by 

 titrating 10 c.c. of the solution from the different flasks at 

 intervals of one to three days. 



Ex. 107. Add about 2 grams of garden soil or decomposing 

 urine to the following solution : 



Di-potassium phosphate ..-'_ . .25 gr. 

 Ammonium sulphate . . ; i.o gr. 

 Urea . ...... 5.0 gr. 



Tap water . *. . . ,- 100 c.c. 

 Incubate at 3 C, ; after forty-eight hours the solution contains 

 urea-splitting organisms chiefly. 



With a drop of this culture inoculate tubes of the following 

 protein-free agar medium suggested by Sohngen. 



Calcium malate . , . 5.0 gr. 

 Di-potassium phosphate ; . .5 gr. 

 Urea . . . . '.'".. 10 gr. 



Agar . ,. .... . 15 gr. 



Tap water . .. . . 1000 c.c. 



Repeat the observations (b) to (d) of previous experiment 

 on the colonies which appear on this medium. 



(ii) Putrefaction in the Manure Heap. Although a 



large amount of the protein substances present in the food of 



an animal is digested and absorbed from the intestinal 



tract, some remains and passes out in the faeces, either 



V 



