304 BOTANICAL GAZETTE [Novewmn 
6. Use of spores of uncertain age and vitality. 
7. Use of culture media unsuited for the normal development 
of the fungi tested. 
8. Imperfect sealing of the cells, due generally to the raising 
of the cover by expansion of contained air when the cultures 
were placed in the thermostat. 
9. Transference of bunches of spores in making inoculations. 
EXPERIMENTAL DATA AND DISCUSSION. 
Details regarding the critical points (¢. ¢., concentrations 
causing injury, inhibition, and death) of the various fungi in the 
more important of the thirty-seven compounds tested may be 
found by referring to the diagrams prepared to accompany this 
paper. This device, primarily intended to conserve space by 
giving.in a condensed form the various specific resistances of 
the different molds will also be useful, it is hoped, in conveying 
to the reader, by means of the eye, a general impression as to 
the relative toxic properties of the agents tested. It should be 
distinctly borne in mind in consulting these diagrams that each 
vertical line represents a doubling of the number of molecules 
present in the solutions in passing toward the right, the vere 
space between two vertical lines representing one concentratio?: 
The relative average toxic properties of the more poisonous 
agents are further graphically depicted by means of he 
charts in the final installment of this paper. Ee 
ACIDS. oe 
In the case of acids, diagrams have been prepared: sO 
the resistances of the individual molds in the eight acice 
diagrams will be found to accompany the diagrams a 
various acids on pages 307-308. In these diagrams a ee 
been made to emphasize the fact that the aie ead of 
concentration in passing to the right, by placing at oe ete 
the columns the proportions of molecules present in Se ore 
tion in terms of x; x being in every case the number an 
“ _ solution. Thus a normal S00" 
262144 = 
cules present in a 
