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A MANUAL OF THE PENICILLIA 



tested in a series of experiments conducted by Raper and Alexander (1945) 

 over a two-year period. It is our belief that this process possesses certain 

 distinct advantages: (1) there is no possibility of contaminants entering 

 the sealed preparations; (2) the investigator recultivating the molds starts 

 with the spores contained in the original suspension; (3) the space required 

 for storage of lyophil preparations is much less than for any other type of 

 culture (fig. 22). 



Fig. 20. Refrigerator adapted for storage of stock cultures of Penicillia and other 

 molds. The flat sliding trays are fashioned of perforated brass sheeting to permit 

 free circulation of air. 



Soil Cultures: Cultures of Penicillia, like many other microorganisms, 

 can be successfully maintained in soil. The method used in our Labora- 

 tory follows that described in 1934 by Greene and Fred at the University 

 of Wisconsin. While this method has not been employed on a scale com- 

 parable with the agar slant method, or the lyophil method, it has given 

 satisfactory results wherever used. Preservation in soil offers the ad- 

 vantage that it enables the investigator to remove source material for sub- 

 cultures from a single stock over a long period of time if proper precautions 



