[Vor. 8 
262 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
balance of sodium and chlorine ions as nearly as possible that of 
the former solution where Na,S,0, and MgCl, were used, a 
sufficient amount of NaCl was added to maintain the balance of 
sodium and change the balance of chlorine only very slightly. 
Ory wt Ce. 
cgms Py loding 
"RN 
90 : "qe 7 
/ 
^. / 
— || 
PA / P 
60 —— 4 / 11 
ait y 
"mad - 
0 7 23 
16 20 
8 12 
Days 
Fig. 8. Penicillium cyclopium on solution of initial Pg containing 
thiosulphate. 
The modified Pfeffer's solution in which the substitutions were 
made is known to be a favorable solution for the growth of many 
fungi, hence this series of cultures was grown to determine if 
there had been any retarding effect of the thiosulphate in solu- 
tions of the same initial Py, as well as the relative changes in the 
hydrogen-ion concentration, the production of H,S, and the 
reversions in reaction in relation to the disappearance of the sugar 
as determined by qualitative tests with Fehling's solution. The 
