112 THE ACTION OF ENZYMES 



the soil. It is a long, motile, rod-shaped organism, 5 or 6 [A 

 long and .8 //, broad. Very resistant spores are formed at 35 C. 

 which arise at one end of the bacillus, the whole becoming 

 the shape of a drum-stick. Bs. putrificus produces a tryptic 

 enzyme, which splits up proteins with the formation of amines, 

 a solution of gelatine being changed into a foul-smelling liquid, 

 with the evolution of much gas, when access of air is pre- 

 vented. 



Ex. 59. Show the production of ammonia from proteins. 

 Prepare the following solution : 



Di-potassium phosphate . . 5 gr. 

 Magnesium sulphate f . 2.5 gr. 

 Sodium chloride . . . 2.5 gr. 

 Water . v . -. i litre. 



Take three 200 c.c. flasks and pour into each 100 c.c. of the 

 solution. 



Add to one . i per cent, of gelatine, 

 another . i per cent of fibrin, 

 a third . i per cent, of peptone, 



and sterilize. 



Inoculate each with Bs. mycoides and incubate at 30 C. for 

 ten to fifteen days. 



(a) Test for ammonia with Nessler's solution. 



(I)} Heat with magnesia, and test the gas given off with 



litmus paper. 

 Control tubes uninoculated should be tested also. 



Ex. 60. Add to a litre of the inorganic solution in previ- 

 ous exercise 



Glucose . . ' .... . . 2 gr. 



Sodium nitrate .' .. . 2 gr. 

 Sterilize: inoculate 100 c.c. of it with Bs. mycoides. Incubate 

 at 30 C., and every second day : 



(i) Test for nitrites (Ex. 74). 



