1919] 



SCHMITZ STUDIES IN THE DECAY OF WOOD 113 



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nique involved in making spore cultures of the two forms is 

 similar. The sporophores were thoroughly rinsed with sterile 

 distilled water to remove as many bacteria and foreign spores 

 of fungi as possible. Since gentle agitation facilitates this, it 

 was found convenient to place the sporophores in sterile wide- 

 necked flasks partially filled with sterile distilled water. After 

 a gentle shaking the sporophores were removed with a pair of 

 sterile forceps, dried with sterile tissue towelling and placed 

 in other similar flasks. By repeating this process three times 

 the surface of the sporophore is found to be comparatively 

 free from bacteria and the spores of foreign fungi. Following 

 this preliminary washing the sporophores were allowed to soak 

 from one to two hours in sterile distilled water, then thor- 

 oughly rinsed and dried as before, and finally placed hyme- 

 nium downward in large sterile Petri dishes. By means of 

 short sterile glass rods the sporophore was kept from resting 

 on the bottom of the Petri dish and thus the possibility of con- 

 tamination of the Petri dish by contact with the sporophore 

 was avoided. In from twelve hours to two days the spores 

 were discharged to such an extent that they were plainly visi- 

 ble on the bottom of the Petri dish. By means of a platinum 

 loop they were removed to a sterile water blank and by the 

 same method were transferred from the water blank to tubes 

 of molten agar and then plated in the usual manner. Trans- 

 fers were made from characteristic colonies from the plates 

 to agar slants. 



A much easier and quicker method, though less certain to 

 be a pure culture, is to place the washed sporophores in Petri 

 dishes containing a small amount of sterile agar. The sporo- 

 phores are not allowed to rest directly on the agar but are kept 

 from it by means of short sterile glass rods lying across the 

 agar. The spores thus fall directly on the nutrient agar and 

 after germination transfers can be made directly to agar 

 slants. Cultures free from contamination were obtained by 

 this method but were not used on account of the decided ad- 

 vantages of the other method. 



In order to avoid growing the fungi on artificial media for 

 any length of time before using them in the decay experiments, 



