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° C. in the serum inspissator. 6. Incubate at 37° C. for forty-eight hours and eliminate any contaminated tubes; store the remainder for future use. ~Egg-albumen (Tarchanoff and Kolesnikoff).~-- 1. Place unbroken hens' eggs in dekanormal caustic soda solution for ten days. (After this time the white becomes firm like gelatine.) 2. Carefully remove the shell and cut the egg into fine slices. 3. Wash for two hours in running water. 4. Place the egg slices in a large beaker and sterilise in the steamer at 100° C. for one hour. 5. Transfer each slice of egg by means of a pair of sterilised forceps to a Petri dish or large capsule. 6. Sterilise in the steamer at 100° C. for twenty minutes on each of three consecutive days. ~Egg Albumin Broth (Lipschuetz).~-- 1. Weigh out Egg albumin (extra fine powder, Merck). 4 grammes and place in a 2-litre flask with a number of sterile glass beads. 2. Measure out distilled water 200 c.c. into a half-litre flask and warm to 37° C. in the incubator. 3. Add the water to the flask containing the albumin and beads and dissolve by shaking. 4. Add n/10-NaOH, 40 c.c. Allow the mixture to stand for thirty minutes with frequent shaking. 5. Filter through Swedish filter paper. 6. Sterilise by boiling two or three times at intervals of two hours. 7. Add ordinary nutrient bouillon 600 c.c. 8. Fill into small Erlenmeyer flasks in quantities of 50 c.c. 9. Incubate for forty-eight hours at 37°C.--discard any contaminated flasks and store the remainder for future use. ~Egg Albumin Agar.~-- 1. Prepare egg albumin solution as above 1-6. 2. Liquefy and measure out ordinary nutrient agar 600 c.c. and add to the egg albumin solution (in place of the nutrient broth). 3. Complete as above 8-9. _Diplococcus Meningitidis Intracellularis._ ~Ascitic Fluid Agar (Wassermann)~ _Synonym_ ~N-as-gar (Mervyn Gordon).~ 1. Liquefy and measure out into a sterile flask: Nutrient agar 600 c.c. 2. Measure out into a half litre flask Distilled water 210 c.c. and add to it Ascitic fluid 90 c.c. Nutrose 6 grammes 3. Heat over a bunsen flame, shaking constantly until the fluid boils, and the nutrose is dissolved.