HOTSON. — CULTURE STUDIES OF FUNGI. 239 



on this subject show undoubted evidence that their investigations were 

 carried on with pure cultures and that the life history from spore to 

 bulbil was closely traced. It is probable that Bainier, Morini, Berlese, 

 and Mattirolo also used pure cultures more or less, but there is little 

 evidence in their writings that there was careful tracing of the fungus 

 from spore to bulbil. 



Sources of Material. 



Before recording the results obtained from the study of the various 

 bulbiferous fungi cultivated by the writer, it will be well to refer 

 briefly to the sources of material and the methods used in this 

 investigation. 



In 1907, at the suggestion of Dr. Thaxter and with a view to obtain- 

 ing as much material as possible for examination, the writer began 

 collecting substrata of various kinds from widely different localities. 

 This material was placed in moist chambers in the laboratory and as 

 bulbils appeared pure cultures were made of them. The methods 

 employed in doing this will be referred to later. Most of the material 

 from which bulbils were obtained was collected either in the vicinity 

 of Cambridge, Mass., or Claremont, Calif.; but bulbils were also 

 procured from substrata received from other portions of New England 

 and California, from Kentucky, Canada, Mexico, Guatemala, Cuba, 

 Jamaica, Bermuda Islands, the Argentine Republic, Italy, etc. 



The substrata on which these fungi were found were very diverse. 

 The most productive were various kinds of excrement (dog, rat, 

 mouse, rabbit, pig, horse, goose, goat, etc.), dead wood (Acer, Lathy- 

 rus, Quercus, Eucalyptus, etc.), decaying vegetables (squash, onions, 

 etc.), straw (wheat, oats, barley, rye, alfalfa, etc.). A number were 

 found on paper and old cardboard, as well as on a variety of other 

 substrata. Of many hundreds of such cultures about two hundred 

 yielded bulbils. 



Culture Methods. 



The moist chambers used for the cultivation of these materials were 

 usually crystallizing dishes covered with pieces of glass. A large 

 amount of this material was grown in the laboratory and from time 

 to time was carefully examined through the glass top with a hand lens. 

 When bulbils were observed, one of them was picked out by means of 

 fine dissecting-needles under a dissecting microscope, and after thor- 

 ough washing in sterilized water on a flamed slide, was transferred to 

 a test-tube containing sterilized nutrient material — usually potato 



