308 BACTERIOLOGY. 



a pea) and place in an incubator. Render another tube 

 slightly acid with dilute hydrochloric acid, and add a 

 bit of the white of egg to it also. Do the results differ? 



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 the 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? 



INOCULATION INTO ANIMALS. As a rule, cultures 

 of this organism obtained directly from the discharges 

 of the wound are capable, when introduced into ani- 

 mals, of producing diseased conditions ; but cultures 

 kept on artificial media for a long time may in part, or 

 completely, lose this power. 



When guinea-pigs or rabbits are inoculated subcuta- 

 neously with 1 c.c. of virulent fluid cultures of this 

 organism, death usually results in from eighteen to 

 thirty-six hours. At the seat of inoculation there are 



