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proper degree of skepticism should be exercised before condemning a 

 preservative on the basis of this test alone. 



Parallel with the use of nutrient substrata of the malt-agar type in 

 this country, there grew up in Europe a technique which utilized the 

 wood itself as a medium for dispersion of the toxic agent. This kolle 

 flask method (Fig. 2) was standardized and accepted by a conference 



Fig. 1 — Assay by petri dish method. Test-fungus No. 517 on increasing amounts 



of coal-tar creosote. 



of European workers at Berlin in 1930.^ An outline of the method 

 follows: Wood blocks of a convenient size are impregnated with the 

 toxic agent, usually in solution, and after evaporation of the solvent 

 the blocks are placed in kolle flasks and supported on glass rods set in 

 malt-agar covered with the actively growing mycelia of the test fungus. 

 The conference advised the use of ConiophorQ cerehella as the test 



