POTATO. 5g 
IV. Media from Meat-extracts. 
(2) Mix thoroughly the white of 1 egg with 
1000 c.c. of water for bouillon or gelatin ; with 500 
c.c. of water for agar. 
(4) Proceed then as directed in the above table, 
beginning with No. 4, substituting ‘‘ white of egg 
solution ’’ for ‘‘infusion.”” At No. 6 add 0.5 per 
cent. of Liebig’s extract of beef for bouillon or gel- 
atin, I.0 per cent. for agar. 
V. Potato. 
(a2) Select large sound potatoes and wash thor- 
oughly. 
(4) Cut off the ends, and with a sterile cork-borer 
cut out cylinders of the potato a little smaller than 
the tubes in which they are to be placed. Handle 
the potatoes under water as much as possible, to 
prevent darkening of the surface. 
(c) Cut the cylinders into two equal parts by a 
diagonal cut. 
(2) Place in cold running water for twelve to 
eighteen hours. This will usually render the 
potato neutral. 
(If necessary to change the reaction of the potato, 
steam in a measured quantity of distilled water for 
one-half hour. ‘Titrate and add the required 
amount of : sodium hydroxid, and repeat the boil- 
ing for thirty minutes.) 
(e) Distribute in tubes in the bottom of which a 
small amount of non-absorbent cotton or a short 
piece of glass rod has been placed, and sterilize in 
