430 
F. D. HEALD AND R. A. STUDHALTER 
which reference has been made, and observations made by Anderson, 
and Babcock (3) during every rain period for the month of August, 
1912. 
It seemed desirable to have continuous records of the behavior of 
definite groups of perithecial pustules through one or more seasons 
under natural field conditions. For this purpose the work presented 
in the following pages was undertaken. 
Method and Plan 
In carrying out this work the first requisite was a means of holding 
a glass slide over a definite area of perithecia-bearing bark. For 
this purpose a wooden bracket was devised. This is a small rectangu- 
lar block, the width of an object slide, carrying a slot at one end for 
1913 
Fig. I. Fig. 2. 
Fig. I. Diagram of ascospore traps, showing the two positions employed; b, 
bracket; ba, hark bearing perithecial pustules; 5, object slide for catching the ex- 
pelled spores. 
Fig. 2. Diagram showing the relative intensity of ascospore expulsion at West 
Chester, Pa., during the season of 1913. 
the insertion of the slide, and attached to the tree by a brass screw 
passing through the center (Fig. i). On some trees the bracket 
was directed downwards, in which case the object slide was held in 
position by a screw turned into the bark (Fig. i, A). In both cases 
the object slide was always wedged firmly into the slot. Ascospore 
