INFECTION-POWERS OF ASCOSPORES IN ERYSIPHACEZ 211 
The rapidity ‘aan which ripe ascospores germinate in water is 
remarkable. In one experiment a ripe but still closed perithecium, 
placed in a ha digits drop of water, was kept under pipes 
water. At th of one and a - out tistor which time 
the slide wth a hanging drop n exposed to the strong 
light of a south window—all ‘iced ascospores had ge ted, 
produced germ-tubes (often from both ends of the spores), which 
leaves were well pounded in sihther in 14 ce, of distilled water, so 
paper, was filtered, and a 20 per ce tion in distilled water 
n hanging drops of this solution four cultures were made, 
d in every case vigorous germination o ascospores occurred, 
After twenty hours strong germ-tubes were produced from nearly all 
the spores : some of these germ-tubes grew, towards the apex, more 
or less vertically into the air. In man cases spores contained in 
the as 
were long (five to eight times the length of the ascospore), and 
vigorous, usually simple but occasionally branched; rarely a few 
mare res a agra 
a 2 per cent. solution of cane-sugar in. 
aistilloa sortie connie excellently, the germination being sHighthy 
more ere than in water. Sown in 1 per cent. solution of 
acetic acid, no germination at all resulted, this amoun id 
repre killing the ascospores, which were turned to a dark-grey 
-colour. In °1 per cent. solution of acetic acid only very 
feoble anaes of a ra spores resulted, the rest after Sanat 
hours having been turned grey and apparently killed. 
The best method of obtaining ripe ascospores is to suspend over 
the opening perithecium a hanging drop of liquid on a rigs 
supported on a wire stand. Many of the por ara: 
have seer sroreniter- large clearly defined oblong or narrowly rec 
angular bodies among the cell-contents. Frequently—at the a 
of twenty to forty hours—a great number (six to os of short. 
germ-tubes will be found to have sprouted out from all p: se 
is ines sh the oe 
by using hanging drops on Sct saa wire stand 
which spaced on wetter peer = at the bottom of eos Pts di 
The incubation period tion-experiments described — 
8 
