1906] FULTON—CHEMOTROPISM OF FUNGI 93 
Sterigmatocystis nigra, Mucor mucedo, and Mucor stolonijer by the 
capillary tube method. | 
It is possible, although there is ‘evidence against it in some of 
the previous experiments, that the diffusion of the solutes might 
be rapid enough to bring about practical uniformity in the media 
before the germination of the spores. To determine whether the 
time at which the stimulus is applied has an influence upon the 
reaction, series were made up with two of the more slowly growing 
species, Botrytis vulgaris and Monilia fructigena, the spores being 
distributed in non-nutrient gelatin placed above the mica plates. 
Four duplicate series were arranged. In one the layers of gelatin 
containing the substances to be tested were placed below the plates 
at the time of making up the cultures; in another series these layers 
were added just as the spores began to germinate; in a third, after 
the most vigorous hyphae had attained a length of 15 to 20 spore- 
diameters; in a fourth when the length equaled 40 to 50 spore- 
diameters. The final counts were made a little later, when the 
growth was about 75 spore-diameters. The results are given in 
Table IV for the five compounds tested and the control. The 
numbers in columns I indicate the average number of hyphae in 
the area around each hole; those in columns II, the percentages of 
turning toward the holes. 
TABLE IV 
Non- 
Hi Ox KH,PO (NH,)NO 
sve Beat] Paar | SSG [mua | MEO | ON | come 
Cres | Appli- 
cation ‘ 
i | ue | I Ir | I | n | I | It I | II I It 
8 of} ar | 35 | xz 38 | 6.3 4-9} 37 | 5-5 | 36 | 9-2 | 34 
a3 £0. 9.6). 38° 1 Gio 1238 Te. | 36.1 §4.) 30 | 72} 36-1 7-61 34 
e6| 13 a) ge fee Tae tat 95.1 6.4.) 3t $14: 33.4 9.21 38 
AE! x6 || 3.3| 30 | 7-6| 34 | 5-5] 3015-8] 35 | 5-0| 32 | 5-6 | 36 
< 
Sa0.0 UG.g1 384-260-140 1 tr] 98 4 3.7) -3t.| 8:2 | 34 | 4-4 [06 
Be 10 9-5 | 36 1 3x ao 4 Es ao. }.3,7 | 38--1.6.8 | 25) 21 -| 32 
S8| ts | 13 | 33 |7-s| 27 | 10 | 32 | 4-3| 30 | 5-4] 27 | 33 | 27 
i} 20 fT  32 ay 16.47 8615-5 1. 20 1 8-1] 26 | 8-3 | go 
It is evident that the time of application has little or no effect upon 
the amount of turning. It will also be seen by comparing these 
