October, 1906] 



Mycological Bulletin Nos. 67 and 68 



267 



use spores from a mushroom as young as possible. If one takes a 

 mushroom just at the time that the veil is breaking, inoculations may 

 be readily made from the spores and few contaminations will result. 

 In this case, by means of a sterile needle, or scalpel, a few spores may 

 be removed from the spore-bearing, or gill, surface and these may be 

 transferred to the tubes in the same way as were bits of the fresh 

 tissue. It is also possible to secure a spore print from a mushroom 

 the gill surface of which has not been exposed to germs of the at- 

 mosphere. In the latter case it is desirable to remove stem and partial 

 veil, peel off the incurved edges of the cap which have been in contact 

 with the soil, and place the cap, gill surface downward, in a sterilized 

 dish or on sterile paper. If this is then kept free from dust, a spore 

 print may be obtained, which should not be contaminated by foreign 

 germs. This print may then be used in making a large number of spore 

 cultures. 



Tissue Cultures. — The suggestion which had presented itself of 

 using bits of living tissue from a sporophore instead of spores seemed 

 also, from genral observations, to be of sufficient importance to war- 

 rpnt a thorough trial. Durirg moist weather, or in a moist cellar where 



Fig. 200. A tiiic cluster >f .\garicus campes-iRis. tlic Horticultural N'ariety Colum- 

 bia. l-"ri m Itullitiu Nc. 85, H. M. Duijsar. liureau of Plant Industry, 

 U. S. Dcpartnunt of Agriculture. 



