Brown . — Studies in the Physiology of Parasitism . IX. 293 
blotting-paper. Eight Petri dishes were allotted to each plant, and eight 
were set up as controls, each lot being subdivided as follows : 
2 with B.P. and containing watch-glass of water. 
2 „ „ „ dil. NaOH. 
2 without B.P. and containing watch-glass of water. 
2 „ „ „ dil. NaOH. 
In each dish were two slides, each with two drops of the same spore 
suspension. There were thus eight drops under each treatment. After 
two days the state of germination was determined. In all cases no 
definite difference could be seen or measured between the germinations 
over water and the corresponding ones over dilute caustic soda, thus again 
showing that carbon dioxide is not the factor concerned. Each figure in 
the table represents the average of twenty- five spores taken from one drop, 
and each set of twenty-five measurements was taken from different drops. 
These figures will also serve to illustrate the degree of uniformity met with 
in these measurements. 
Table V. 
Experimental condition. 
Amount of germination after 2 days. 
Average. 
Without blotting-paper. 
Control 
2-12, 1. 60, 2.08, 1 *88, ) 
1 ‘ 5 °> W 2, 1-56, i-6o \ 
1.76 
Apple 
3.44, 3.16, 3.12, 3.24 
3 ,2 4 
Orange 
Inhibition in all cases 1 
0-00 
Eucalyptus 
5-^4 
5.84 
Potato 
0.44 2 
0.44 
With blotting-paper 
Control 
0*14, 0.10, 0.14, 0.16, 
0.14 
Apple 
2-96, 2.92, 2.72, 2.92 
2.88 
Orange 
Inhibition in all cases 1 
0-00 
Eucalyptus 
3.16, 2.88 
3.02 
Potato 
Almost completely inhibited 
0-0 + 
This experiment shows clearly the following points : 
(1) That Botrytis spores are distinctly stimulated by the presence of 
apple tissue and of Eucalyptus leaves. 
(2) That orange rind and potato tubers produce equally distinct 
depression of germination. 
(3) That the presence of wet blotting-paper depresses germination. 
Again it may be noted that the stimulating effect is best seen in the 
series where the control germination is feeble (i. e. when blotting-paper is 
present), whereas the retarding effects show best in the series where 
blotting-paper is absent and where accordingly the control germination 
is good. 
Though the spores of Botrytis cinerea were found to be the most 
1 Incipient germination on 4th day. 
2 This was the best germination seen in any of the eight drops. 
