1919] 



ZELLER, SCHMITZ AND DUGGAR FUNGI ON LIQUID MEDIA 139 



The cultures were incubated at room temperature (about 15- 

 25° C.) during a period of 30 days. 



The growth of the fungi which is reported in values of X 

 in the table was determined as follows : The culture of maxi- 

 mum growth in the whole series was arbitrarily designated as 

 10 X , no growth as 0, and intermediate amounts of growth as 



1 X,2X,3x,etc. 



The H ion concentrations were determined in accordance 

 with the methods devised by Clark and Lubs, 1 and are given 

 in P H exponents. In the table are given the P H values of the 

 control flasks, the P H values of the solutions after the fungi had 

 grown in them for thirty days, and the amount of change in 

 the H ion concentration of the solutions brought about by the 

 growth of the various fungi. If the change due to growth of 

 the organism is toward the alkaline side from the true neutral 

 point (P H 7) it is designated as minus and if toward the acid 

 side, plus. 



Discussion 



The data presented in the table bring out some interesting 

 features concerning the comparative growth of the fungi in- 

 volved. There is a decrease in the amount of growth of Len- 

 zites vialis, Daedalea confragosa, D. quercina, Trametes 

 Peckii, Merulius lacrymans, Lentinus lepideus, Coniophora 

 cerebella, Polyporus lucidus, and Polystictus hirsutus when 

 passing from the mono- to the tribasic potassium phosphate in 

 Czapek's solution. In Merulius pinastri there is a slight in- 



while 



of Polystictus versicolor is irregular when 



same direct 



In Reed's solution there is a decrease in the growth quanti- 

 ties of all of the fungi, except Pleurotus sapidus, Merulius 

 lacrymans, and Coniophora cerebella, when passing from the 

 mono- to the tribasic potassium phosphate. In Pleurotus sapi- 

 dus growth is equal in all cases, in Merulius lacrymans there 

 is a steady increase, while in Coniophora cerebella it is irregu- 

 lar. 



l Clark, W. M., and Lubs, H. A. The colorimetric determination of hydrogen 

 ion concentration and its applications in bacteriology. I. Jour. Bact. 2: 1-34. 



1917. 



