248 RESEARCHES ON FUNGI 



thereto. Action and reaction being equal and opposite, the asci of 

 S. protracta, since they have an obhque direction of discharge, might 

 well fail in effectiveness were it not for the well-developed para- 

 physes which prevent the end of each ascus from moving in a direc- 

 tion opposite to that of the projectiles (spores and drops of cell-sap) 

 whilst the discharge is actually taking place. 



That the discharge of the spores from each ascus takes place in a 

 hne which is very obhque to the ascus-axis can be well demonstrated 

 by two experiments, one made in the air and the other in water, as 

 follows : 



(1) Using a sharp scalpel and working rapidly, one cuts through 

 a fruit-body which has been lying in a Petri dish and is ready to 

 puff, so as to isolate a piece of the apothecium extending from the 

 rim to the base. This fragment is taken in the fingers and held 

 horizontally with the hymenium looking upwards. Pufhng then 

 takes place, and one can observe that the spores are shot away not 

 perpendicularly to the hymenial surface but obliquely upwards 

 towards the rim-end of the fragment. For an illustration of what 

 one sees, one may imagine that the surface of the hymenium shown 

 on the right-hand side of Fig. 120, A, has been placed in a horizontal 

 position and that the direction in which the spores are shot is shown 

 by the arrows in their new positions. 



(2) With a hand-razor one cuts a longitudinal-radial section 

 through one side of an apothecium containing almost ripe asci and 

 mounts it in water under a cover-glass. It has the appearance of 

 the right or the left half of Fig. 120, A. One then places a drop of 

 iodine at the edge of the cover-glass so that it gradually diffuses over 

 the hymenium beginning at one end and passing slowly to the other 

 end. As the iodine acts on the asci, they explode one by one in 

 succession, and one can readily observe that the eight spores of each 

 ascus are shot obliquely through the water toward the rim-end of 

 the hymenium. One sees each ascus explode and contract {cf. A 

 and B in Fig. 120), but the spores are shot away with such speed 

 that one does not see them passing through the water until they have 

 almost been brought to rest by the resistance of the water. As the 

 iodine continues to diffuse over the section, hundreds of asci explode 

 and the spores accumulate on the surface of the slide as a thick 



