POTATO MEDIA 49 



4. Wash the hands in sublimate solution, remove the potatoes, 

 and cut in two with a sterilized potato-knife. 



5. Lay the cut pieces of potato in plate culture dishes with a 

 piece of filter paper previously soaked in the sublimate solution in the 

 bottom of the dish. ' The potatoes are not used until cold.'' 



6. Use the platinum loops to inoculate the cut surface of the 

 potatoes, and spread the material over the desired amount of surface 

 with a sterilized potato-knife. 



LXXVII. ESMARCITS METHOD. 



1. Thoroughly wash some potatoes. 



2. Peel and cut off the ends. 



3. Cut into sections 1 cm. thick and place in clean water. 



4. Place the slices in Esmarch dishes. 



5. Sterilize in the steam sterilizer three-quarters of an hour. 



6. If the Esmarch dishes are not sterilized before the slices of 

 potato are put in, then sterilize on each of three successive days as 

 follows : 



First day, for 30 minutes ^ 



Second day, for 15 to 20 minutes \ In the steam 



Third day, for 15 to 20 minutes J 



LXXVIII. ROUX AND GLOBIG'S METHOD. 



1. Some potatoes are thoroughly washed, the ends cut off, bored 

 through with a cork-borer, and the cylindrical pieces of potato laid in 

 water. 



2. The potato cylinders are cut diagonally in two and placed 

 again in water. 



3. Take some ordinary test-tubes, place some cotton wadding or 

 a piece of glass rod in the bottom, add a little water, put a piece of 

 potato in, and shake it down until it touches the material in the 

 bottom of the tube, plug the tube with cotton wadding. 



4. Potatoes as a rule have a slight acid reaction, and to render 

 them faintly alkaline, lay the potatoes in a 1 per cent, solution of 

 sodium carbonate before placing in the tubes or before sterilizing. 



5. Sterilize on each of three successive days as follows : 



First day, for 30 minutes ^ 



Second day, for 15 to 20 minutes In the steam 



Third day, for 15 to 20 minutes J sterilizer. 



D 



