PREPARATION OF MEDIA 85 



Serum bouillon media (Marmorek's media). 



1. Human serum, 2 parts; nutrient bouillon, 1 part. 



2. Ascitic or pleuritic fluid, 1 part; nutrient bouillon, 

 2 parts. 



3. Horse serum, 1 to 2 parts; nutrient bouillon, 1 to 2 

 parts. 



These media were first used extensively by Marmorek in 

 cultivating streptococci. The ascitic fluid bouillon has been 

 found by Williams to be of great use in enriching cultures of 

 diphtheria bacteria. It is also the best medium for the 

 growth of pneumococci, streptococci, and many other patho- 

 genic bacteria. 



Serum-water media (Hiss' serum media). When diluted 

 with 2 to 10 parts of water, many sera can be steamed with- 

 out coagulating. 



1. Ox serum, 1 part ; distilled water, 2 parts ; normal 

 sodium hydrate, 0.1 per cent. 



2. The same, with inulin 1 per cent substituted for the 

 sodium hydrate. 



For the sterilization of undiluted fluid serum and of 

 ascitic and pleuritic fluids, it is requisite that it be exposed 

 to a temperature of from 62 to 66 C. for one hour on each 

 of six consecutive days. The best apparatus for obtaining 

 and maintaining this temperature (about 65 C.) is a small 

 and well-regulated incubator or chamber surrounded by a 

 water space, into which the tubes and flasks containing 

 serum are to be put each day, and in which they are to be 

 left for the prescribed time after having been warmed to the 

 desired temperature: 



Serum may be preserved by placing it in flasks which, 

 after the addition of 5 per cent chloroform, are sealed. 

 When it is to be used it is poured into sterilized culture 

 (test) tubes and sterilized by exactly the same methods as 

 are employed in sterilizing fresh serum. The chloroform, 

 being volatile, tends to disappear at ordinary temperatures, 

 but is quickly and surely driven off at the temperatures used 

 in the sterilization. 



