288 Brown. — Studies in the Physiology of Parasitism. IX. 
were made as it was judged w.ould give an adequate representation of this 
impression. In many cases the differences were so pronounced that 
a limited number of measurements served for this purpose. Where the 
differences were less marked, more measurements were taken. In some 
cases, where differences appeared over even a large number of measure- 
ments, and where examination of all the drops gave no definite impression 
of difference, the results of measurement were ignored. The conclusion in 
such cases was that differences, if they did exist, were not large in amount, 
and therefore, in exploratory work such as the present is, the fuller examina- 
tion of such effects should be postponed until such time as it appeared that 
the subject demanded it. The claims made in the present paper are on 
a very conservative basis, and are confined to the major and obvious results 
met with in the course of the work. 
Most of the observations were made with spores of Botrytis cinerea , 
which proved in all respects to be the most convenient fungus for this work. 
Tests were also made with spores of Botrytis parasitica (. Allii , the form 
occurring on onion), Monilia fructigena , P enicillium. glaucum , Fusarium sp., 
and Collet otrichurn B indent u th ian u in . 
The list of plants tested was as follows : petals of Rosa centifolia , 
leaves of Rnta macrophylla , Santolina Chamaecyparissus , Eucalyptus 
globulus , Pelargonium zonale , Choisya ternata , Chrysanthemum (garden 
vars.), Lavandula spicata , Foenicidum vulgar e, Fuchsia (garden var.), Vicia 
Fab a, Melittis metis sophy llum , Amomum cardamomum , Andropogon 
Schoenanthus, Allium Schoenoprasum , Agapanthus umbellatus ; bulb scales 
of onion ; fruits and leaves of apple ; rind of orange fruit ; and tubers of 
potato. 
The following table is typical of the result obtained when a few (one or 
two) bruised leaves are placed in Petri dishes side by side with slides on 
which lie drops of a suspension in water of spores of Botrytis cinerea. 
Moist blotting-paper was present in the Petri dish-lids in all cases. Spores 
of two different ages were used, the older giving feebler germination in 
water. In the case of the controls the figures are the average of ioo counts ; 
the others are based on 50 counts. The measurements of germination were 
taken two days after the start of the experiment. 
Table I. 
Old spores. 
] 'oung spores. 
Control 
0*07 
2.03 
Amomum 
0.94 
3.48 
Eucalyptus 
0.52 
2.60 
Santolina 
0.60 
3-44 
Ruta 
1.74 
3-68 
Allium 
0.00 
0*00 
Choisya 
2.16 
5.08 
Lavender 
0.32 
similar to control 
Agapanthus 
0.96 
3-08 
Apple (leaves) 
2.16 
5.00 
