PSEUDOMONAS MRUGINOSA 389 



Heat another tube to 80 C. for fifteen minutes, and 

 repeat the experiment. Has the heating had any effect ? 



To another tube add carbolic acid to the extent of 2 or 3 

 per cent. Is the digestive activity of the solution modified? 



To two ordinary tubes of gelatin add carbolic acid 'until 

 it is present to the extent of 0.25 per cent, in each tube. 

 Solidify the gelatin in one tube in the upright position; let 

 that in the other remain fluid. On the surface of the former 

 pour 0.5 c.c. of the pyocyaneus filtrate, and mark the point 

 of contact between the gelatin and filtrate. To the other 

 tube add a similar amount of filtrate, mix thoroughly, and 

 solidify in a glass of cold water. 



At the end of eighteen to twenty hours note result. Is 

 it possible to solidify again the gelatin through which the 

 filtrate was mixed, by placing the tube in cold water? 



Do the activities of this enzyme suggest those of any of 

 the enzymes encountered in the animal body? Which? and 

 Why? 



Extract with chloroform a six days' old bouillon culture 

 of this organism. In which portion of the liquid so extracted 

 is the proteolytic ferment contained, the chloroform extract 

 or the supernatant fluid? 



Mix slowly a two weeks' old bouillon culture of this 

 organism, grown at body temperature, with six times its 

 volume of absolute alcohol. Allow to stand over night. 

 Filter. Redissolve the precipitate in a few c.c. (5 or 6), of 

 physiological salt solution. In the meantime evaporate the 

 alcohol filtrate to dryness at a temperature not exceeding 40 

 C., and redissolve the sedement in 5 or 6 c.c. of physio- 

 logical salt solution. Test both of these solutions on car- 

 bolized gelatin for proteolytic activity. What are the 

 results and how are they explained? 



