), and mix thoroughly.

4. Heat in the steamer for twenty minutes.

5. Weigh out 15 grammes agar, emulsify in a separate vessel with 200
c.c. of the alkaline fluid previously cooled to about 20 deg. C., and
then add to the remainder of the fluid in the flask.

6. Bubble live steam through the mixture for twenty minutes to dissolve
the agar.

7. Filter through papier Chardin, using a hot-water funnel.

8. Weigh out glucose 10 grammes (= 1 per cent.), and dissolve it in the
clear agar.

8a. If desired, add glycerine, 5 per cent., to the clear agar.

9. Tube, and sterilise as for nutrient agar.

~Serum Agar (Libman).~--

1. Prepare nutrient agar (_vide_, page 167) using, however, 1.5 per
cent. peptone (that is 15 grammes per litre instead of 10 grammes).

2. Adjust the reaction to 0 (i. e., neutral to phenolphthalein).

3. Filter and transfer 1000 c.c. liquefied medium to a sterile flask.

4. Weigh out dextrose 20 grammes and dissolve in the fluid agar.

5. Tube in quantities of 6 c.c.; and sterilise in the steamer at 100
deg. C. for thirty minutes on each of three consecutive days.

6. After the third sterilisation cool to 42 deg. C. and add to each tube
3 c.c. of sterile hydrocele fluid, ascitic fluid or pleuritic effusion
(previously sterilised, if necessary, by the fractional method); allow
the tubes to solidify in a sloping position.

7. When solid, incubate at 37 deg. C. for forty-eight hours, and eliminate
any contaminated tubes. Store the remainder for future use.

~Egg-albumen, Inspissated.~--

1. Break several fresh eggs (hens', ducks', or turkeys' eggs), and
collect the "whites" in a graduated cylinder, taking care to avoid
admixture with the yolks.

2. Add 40 per cent. distilled water, and incorporate the mixture
thoroughly by the aid of an egg-whisk.

3. Weigh out 0.15 per cent. sodium hydrate and dissolve it in the fluid
(or add the amount of dekanormal caustic soda solution calculated to
yield the required percentage of soda in the total bulk of the
fluid--i. e., 0.375 c.c. of dekanormal NaOH solution per 100 c.c. of
the mixture).

_3a._ Glucose to the extent of 1 to 2 per cent. may now be added, if
desired.

4. Strain the mixture through butter muslin and filter through a
porcelain filter candle into a sterile filter flask.

5. Tube, and stiffen at 100 deg. C. in the serum inspissator.

6. Incubate at 37 deg. C. for forty-eight hours and eliminate any
contaminated tubes; sto