GERMINATION STUDIES. 

 Table II. — Efflciencij of salts on various media. 



17 



" Watered with concentrated solution of magnesium phosphite. 



' Watered with strong solution of magnesium potassium ammonium phosphate. 



Large test tubes were used in these experiments, and duplicate 

 cultures were made in every instance. From these and from numer- 

 ous other cultures it was ascertained that germination could not be 

 obtained invariably, even on favorable media and under pure-culture 

 conditions, by the use of these partial stimuli. Nevertheless, the 

 percentage of failures has usually been small. By means of the 

 stimulus given by magnesium phosphite it has also been possible to 

 get growth from the spores in test-tube cultures with gray filter 

 paper as the solid substratum and various plant decoctions and cul- 

 ture solutions as the nutrients. Details of these results, however, 

 may be omitted. 



In many cases it has been possible to obtain growth from the 

 spores by the use of the stimulating salts Avhich have been mentioned 

 in connection with the germination studies. Where it is desired to 

 make experiments along this line the writer has found it more 

 practicable to 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 contami- 

 nations 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 Avere 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 atmosphere. In the latter case it is desir- 

 able 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. 



Experiments were also made in which pots of unsterile composts 

 and manures were inoculated, on the one hand, with spores, and, on 



