64 



A MANUAL OF THE PENICILLIA 



I'/O 



Wort-gelatine-agar according to Biourge. Biourge prepared his wort-gelatine-agar 

 substratum by dissolving 1.5 per cent of agar-agar in the wort, autoclaving at 120°C. 

 for a half hour, then adding an equal quantity of wort containing 10 per cent of gela- 

 tine, and sterilizing the mixture at 110°C. for fifteen to twenty minutes. Biourge's 

 latin diagnoses appear to have been based upon cultures made with this substratum. 



Both Sopp and Biourge regarded wort in some variety as a standard 

 substratum for Penicillia, and it may be so regarded if reference is made 

 merely to a substratum in which almost any PenicilUum will grow. Wort 

 and allied substances, however, are chemically very complex, and analyses 

 of biochemical activities based upon reactions obtained are very difficult to 

 determine. It is not uniform in successive lots or in different laboratories, 

 and the color of the wort itself masks color reactions produced by many 

 fungi. Nevertheless, it is very useful, especially for maintaining stock 

 cultures of certain species which do not thrive upon synthetic media. 



MEDIA USED IN THE PRESENT STUDY 



Czapek's Solution Agar 



Our collaboration with chemists upon the study of the biochemical 

 activities of molds very early pointed to the desirability of a basal cultiu-e 

 solution whose components were readily available in the stock room of 

 any chemical or mycological laboratory. For this purpose Dox (1909) 

 selected the general combination of reagents attributed to Czapek. The 

 selection was intended to present each element in a single form as nearly 

 as possible, thus permitting the elimination or substitution of single com- 

 ponents and the determination of their significance in metabolism. 



Water 1,000 cc. 



NaNOs 3.0 grams 



K2HPO4 1.0 gram 



MgS04-7H20 0.5 gram 



KCl 0.5 gram 



FeS04-7H20 0.01 gram 



Sucrose (Cube or other good commercial grade) 30.0 grams 



Agar 15.0 grams 



To reduce caramelization the sugar is added just prior to final sterilization. 



ulture data upon Penicillia grown in this type of medium have been 

 accumulating in our laboratories since about 1909. In general, it cannot be 

 claimed to be an optimum solution for Penicillia, but with a limited num- 

 ber of exceptions the species studied Avill grow and produce characteristic 

 colonies upon such media. Oftentimes, failure to grow well becomes a 

 negative character of great usefulness. Transfer back to Czapek's solu- 

 tion agar, from whatever other culture medium we have tried, has usually 

 brought back the colony characters originally recorded. Such a synthetic 



