40 
sodium hydrate. The reaction is indicated by the first appearance 
of a distinct rose-red color, best seen in a white porcelain dish before i 
a well-lighted window. 
Example: 2.6 c. c. of the ^ NaOH solution is found necessary to i 
neutralize 5 c. c. of the bouillon in order to obtain the desired acidity 
of 0.5 per cent, add 2.1 c. c. (2.6— 0.5 = 2.1), of the normal soda solu- 
tion (10 to 1,000) to each 100 c. c. If an acidit}" of 1.5 per cent is ! 
desired, add 1.1 per 100 c. c. (2.6— 1.5 = 1. 1). 
Each lot of bouillon is numbered and a complete record kept of } 
every stage of the operation upon the blank shown in fig. 6.^^ i| 
The bouillon is distributed in modified Fernbach flasks, presenting j 
a large surface to the air for pellicle growth. Seven hundred and fifty | 
c. c. of the bouillon is placed in each flask. | 
The fresh 1}^ prepared media is inoculated upon the surface from a ] 
twenty-four-hour-old culture by means of a platinum spoon. 
The flasks are incubated for seven da}^s at 37.5° C. 
They are then removed and examined for purit}" by means of cover 
slips. All at3"pical growths are discarded. i 
The final reaction of the culture when taken from the incubator is 
taken for each flask. This usuall}" varies from 0.6 to 0.8 per cent. 
Veiy acid results, such as 1.5 or over, would, according to Smith’s 
work, indicate the absence of a strong poison and may be discarded 
without further testing upon guinea pigs. * 
The bouillon is now filtered through a pear-shaped, unglazed porce- I 
lain filter or a Berkefeld candle b}" means of a vacuum. The arrange- 
ment for filtering the virus is shown on page 38. This diagram also 
illustrates the character of the flask used to store the toxine in bulk. 
It is veiT convenient to draw ott' small amounts from time to time by 
means of the siphon and Maasen nozzle without danger of contamina- ■ 
tion. The especially strong and otherwise suitable toxines are bottled i 
from these flasks without the addition of aii}^ preservative. 
Bottling and j)Teserving . — The toxine is kept in bulk in the 2 liter ; 
bottle shaped flasks described above, and later divided into small i 
ground-glass stoppered bottles holding 5 and 10 c. c. each. ! 
The small bottles are filled to the neck with the toxine and the | 
stopper inserted so that the air is all displaced and the fluid completeh" 
fills the vial. 
A minute quantit}^ of sterilized liquid petrolatum is touched to the . 
ground glass of the stopper so as to prevent the two surfaces of glass 
am indebted to Dr. Herbert D. Pease, director of the antitoxin laboratory, i 
New York State department of health, for suggestions on the method of 'keeping , 
records on the card system shown in tigs. 4 and 6. Doctor Pease very kindly let 
me have blanks used by him, which were modified to suit our purposes. 
