g2 BOTANICAL GAZETTE [FEBRUARY 
the medium containing the chemical and that containing the spores 
could be more nearly equalized in amount and in consistency; fewer 
hyphae would take a course that would lead them through the open- 
ings without apparent turning; better sterilization could be secured; 
and there was less difficulty in making up the preparations. 
In making the counts, hyphae within a radius of one opening 
diameter from the margin of each opening were considered; the 
hyphae within such an area were classed in the counts as those 
turning toward the openings, those turning away from the openings, 
and those apparently indifferent. After an examination of the 
entire preparation in each case, those holes were selected for the 
counts which represented the average condition. In calculating 
the percentages from the counts, the difference between those attracted 
and those repelled was made the dividend, and the total number 
within the observed area was made the divisor. The results are 
shown in Table ITI. 
If the percentages of turning toward distilled-water gelatin as 
determined by the control experiments, be deducted from the per- 
centages of turning toward the various chemical compounds, it will 
be found that in only three instances would the difference, which 
would be supposed to indicate the amount of turning due to chemical 
influences, approximate 25 per cent., or about the average of the 
lowest of the several degrees of positive chemotropism recognized 
by Mryosui. Most of the values, even for supposedly highly attract- 
ive substances, are very near the controls. 
Evidently, the results thus far have not been favorable to the 
theory of chemotropism. But it was thought that the fungi, all of 
which grew perfectly normally in gelatin made up in distilled water, 
might turn more strongly from some other medium in which there 
was less of available nutriment, to one having an abundance. In 
agar made up with distilled water, the fungi germinated after a 
greater length of time and grew more slowly; but the turning from 
this non-nutrient agar toward a nutrient salt solution favorable for 
fungous growth was no more marked than from agar containing the 
same proportions of the nutrient salts to the nutrient salt solution; 
nor did the nutrient solution seem to attract from either medium 
more strongly than ‘did distilled water. This test was made with 
