240 PROCEEDINGS OF THE AMERICAN ACADEMY. 



agar. In the case of some melanosporous forms the transfer was made 

 by carefully touching the long cirri of ascospores, produced by the 

 perithecia of this genus, with a piece of nutrient agar on the end of a 

 sterilized platinum needle. The ascospores adhering readily to the 

 agar, a pure culture was easily obtained. 



Bacteria sometimes gave trouble in some transfers, but as a rule 

 these were gotten rid of either by picking out separate bulbils carefully 

 and washing several times before growing them in acidulated nutrient 

 agar, or by keeping the impure tubes at a temperature of 15-20° C. 

 The growth of the bacteria being retarded either by the cold or acid, 

 the mycelium producing the bulbil soon grew out beyond the affected 

 region, and by gouging out a few of the ends of the hyphae with some 

 of the agar and transferring to another tube, a pure culture was readily 

 obtained. 



When these were secured the fungus was cultivated on various 

 kinds of nutrient agar media, some growing better on one medium and 

 some on another. The following were used most frequently : potato, 

 onions, sucrose of different percentages, bran, rice, cornmeal, straw, 

 plums, prunes, grapes, figs, bread, squash, Spanish chestnuts, wood, 

 various kinds of dung, etc. These were usually used with agar, but 

 some materials like wood, dung, straw, nuts, etc., were sterilized in 

 bulk with plenty of water and without using agar while in some 

 instances decoctions were used. In Claremont, California, they were 

 grown in the laboratory at an average temperature of 25-30° C. 

 In Cambridge many were grown in an oven kept at various constant 

 temperatures, 20-25° C. giving the best results. 



The vessels used for these cultures were usually medium sized test- 

 tubes, Erlenmeyer flasks of one and two litres, or preserve-jars with 

 cotton plugs. These were filled about one-third full of nutrient agar 

 and usually slanted to give more surface. On this nutrient the fungus 

 would usually grow well for several months, and results were often 

 obtained from pure gross cultures which could not be secured from 

 the smaller ones. 



In the germination of the spores and bulbils. Van Tieghem cells 

 were used very freely. For this purpose cover glasses of one inch 

 and two inches in diameter were used and carefully sealed, plenty of 

 sterilized water having previously been put in the cells which corre- 

 sponded in dimensions with that of the cover glasses. The large 

 Van Tieghem cells afforded an opportunity of using cultures of con- 

 siderable size which were usually composed of decoctions of different 

 kinds of nutrient material, sometimes with agar to make them solid, 

 while at other times the decoctions were used as hanging drops. 



