252 An Introduction to Medical Mycology 



1. Add the agar to 700 cc. of the water and soak for one hour. 



2. Add the peptone and dextrose to the remaining 300 cc. of water. 

 Stir for a few minutes until both ingredients are dissolved. 



3. Cook the agar and water in an aluminum pot, stirring occasionally. 



4. When the agar is almost dissolved, start to cook the peptone and 

 dextrose mixture; stir. 



5. When both the agar and the peptone and dextrose are dissolved, add 

 the peptone and dextrose to the agar and stir. 



6. Measure the mixture into test tubes. 



7. Autoclave the tubes for 20 minutes at a pressure of 15 lb. 



8. Slant the tubes and leave them until the medium is solid. 



DEXTROSE BROTH 

 A liquid medium of simple structure may be useful in studying yeastlike 

 fungi, to flood certain growths on a solid medium or in the preparation of 

 massive growths for use in making extracts. 



Dextrose (crude American) 40 Gm. 



Peptone 10 Gm. 



Distilled water 1,000 cc. 



The method used in making dextrose agar should be followed. 



CONSERVATION AGAR 

 This was advocated by Sabouraud to prevent the loss of the character 

 of the colony through excessive vegetative growth. We find that unless 

 one is careful the colony may die because of slowness of growth on the 

 conservation medium. The method of making conservation medium is 

 similar to that of the ordinary dextrose agar, the only difference being the 

 omission of dextrose from the former. 



11 desired, 20 Gm. of technical maltose may be included. The colony is 

 then neither too luxuriant nor too scanty and the characteristics of the 

 culture remain constant. 



CORN MEAL AGAR 

 This is used in the differentiation of various species of Monilia and Cryp- 

 tococcus. It is also useful when one is studying the spore forms of the 

 dermatophytes. Its value is partly due to a minimal nutrient content; the 

 growth, while scant, shows the characteristics of fructification. 



