DISSOLVING GELATINE 165 



2 . Measure out double strength meat extract, 500 c.c., 

 into the " tared" flask. 



3. Weigh out and mix 10 grammes of peptone, 5 

 grammes of salt, and make into a thick paste with 150 

 c.c. distilled water; then add the emulsion to the meat 

 extract in the flask ; also add 100 grammes sheet gelatine 

 cut into small pieces; place the flask in the water- 

 bath and raise to the boil. 



FIG. 108. Arrangement of steam can and water-bath for the preparation 



of media. 



4. Arrange a 5 -lit re tin can (with copper bottom, 

 such as is used in the preparation of distilled water) 

 by the side of the water bath, fill the can with boiling 

 water and place a lighted Bunsen burner under it. 

 Fit a long safety tube to the neck of the can and 

 also a delivery tube, bent twice at right angles; 

 adjust the tube to reach to the bottom of the interior 

 of the flask containing the gelatine, etc. (Fig. 108). 



