CULTIVATION AND PRESERVATION OF PENICILLIA 63 



preparation have been reported with consequent variation in the richness 

 and texture of the resulting media. The preparation marketed by the 

 Digestive Ferments Co. (Difoo) may be regarded as representative. It 

 contains the following ingredients: Infusion from 50 grams dried potatoes; 

 20 grams dextrose; and 15 grams agar per liter of water. The pH should 

 approximate 5.6. 



Licorice Sticks 



In his descriptions, Bainier failed to specify the type of culture vessel 

 emploj^ed or the substratum upon which his cultures were grown for 

 diagnostic observations. However, many references are made in his dis- 

 cussions to the use of licorice sticks for culture purposes. The cultures 

 seen in his laboratory in 1905, and others received from Gueguen at his 

 laboratory, were grown upon licorice sticks in constricted tubes containing 

 water. Onlj^ such essential data regarding colony characters as could be 

 made upon these licorice sticks is presented in Bainier's papers, hence we 

 assume their routine use in his hands. This limitation adds greatly to the 

 difficulty of interpreting his descriptions. Cultures upon licorice sticks 

 grow well and maintain their vitality for a long time, but in our experience 

 have proved exceedingly unsatisfactory in separating organisms closely 

 related in the various groups. 



Prune Gelatine 



Westling's descriptions (1911) were based upon an infusion of about 

 10 prunes to a liter of water. To this he added 15 percent gelatine to 

 produce a mass firm enough to be handled in petri dishes. Our own cul- 

 tures with this medium were entirely satisfactory for general purposes, but 

 we abandoned the formula because it cannot be defined accurately enough 

 to insure uniformity when prepared in widely separated laboratories. 

 The complexity of the nutrients present nullifies its value for biochemical 

 studies. At best it has no advantage over the wort type of culture 

 medium . 



Wort or Beer Wort 



Brewery wort, or beer wort, formed the basis of much of the media used 

 by Wehmer, Sopp, Dierckx, Lindner, Biourge, and many other workers. 

 Few of them specified the characteristics of the basic nutrient. Biourge 

 (1923) alone offered some general limitations. 



Wort according to Biourge. Select a pale wort (from the brewery) before the addi- 

 tion of hops, autoclave for fifteen minutes at 115 to 120°C., filter in the boiling condi- 

 tion, distribute in tubes or flasks, and sterilize fifteen minutes at 120°C. The density 

 at 4.8°C. to 4.6°C. should be 12 to 14° Balling. 



