[Vor. 8 
94 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
solution with an initial of P, 7.0 and a final reaction of 7.9 
afforded maximum results, but only slightly less accumulation 
occurred at Py 8.2. Culture solutions of Py 3.0 and P, 4.5 
were equally favorable in the case of Penicillium italicum. 
3. Amylase accumulated more abundantly in the cultures of 
C. Gossypii than in the other fungi studied. 
4. A gradual decrease in the amylase accumulation was effected 
by Fusarium as the culture solution became more alkaline, this 
decrease not being coincident with a reduction in the amount of 
growth. 
5. An increase in accumulation occurred in the intra- and 
extracellular amylase of C. Gossypii as the nutrient solution 
became less acid, neutral or alkaline solutions being most effect- 
ive. 
6. 'The intra- and extracellular amylase, produced by any one 
fungus under varying H-ion concentrations of the culture solu- 
tion, had similar properties with respect to the effect of the 
reaction of the NaOH-H,PO, buffer solution upon activation. 
7. An optimum zone of activity, between P, 3.0 and P, 6.0, 
existed for P. italicum, while in the other fungi the optimum was 
more sharply defined at P, 6.0 when the activity was measured 
in the buffer solution at 28? C. for 24 hours. 
8. Complete inactivation occurred at Py 8.0 for the amylase 
of P. italicum. Under similar amounts of amylase accumula- 
tion by Fusarium and C. Gossypii, inactivation was effected by 
solutions of Py 9.0 to 11.0. 
9. A decrease in the actual acidity of the culture solution 
occurred in all of the series of P. italicum and all but the most 
alkaline, or Py 9.2, series of Fusarium and C. Gossypii. The 
former produced no change in the reaction of this culture solu- 
tion, while the latter caused a slight shift toward neutrality. 
Acknowledgements are due Dr. B. M. Duggar, under whose 
direction the work was carried out, for helpful advice and kindly 
criticism; and Dr. G. T. Moore for the privileges and facilities 
of the Missouri Botanical Garden. 
Graduale Laboratory, Missouri Botanical Garden. 
