PUFFING IN THE DISCOMYCETES 259 



When the apparatus was set up, fruit-bodies were removed one 

 by one from the Petri dishes with the fingers as required and were 

 held at the mouth of the test-tube as shown in Pig. 124 at h. It was 

 necessary to carry out each of these operations as rapidly as possible 

 because, if a fruit-body was in a condition to puff, it usually puffed 

 within three seconds of raising the Petri-dish lid. With the pro- 

 cedure just described some of the fruit-bodies were caused to puff 

 into the mouth of the test-tube a. 



Immediately after placing a fruit-body at the mouth of the test- 

 tube a, I looked towards the black back-ground shown at i and then, 

 within a second, if the fruit-body puffed strongly, I heard the fungus 

 hiss for about two seconds and saw a cloud of spores shoot out from 

 the side-pipe b. In the most successful experiments the spore-cloud 

 was carried horizontally, as shown at i in Fig. 124, a distance of 

 about three inches beyond the mouth of the side-pipe b before 

 irregular dispersion took place ; but in several other experiments 

 the distance was not more than about 1-1*5 inches. Since the 

 spores cannot be shot by any ascus around a corner, it seems clear 

 from these experiments that the fruit-bodies, on puffing, must create 

 a blast of air which can carry the spores passively with it. 



To vary the experiment just described, I suspended a strip of 

 thin tissue-paper four inches long, one-tenth of an inch wide at the 

 top, and six-tenths of an inch wide at the bottom, so that its lower 

 end was just in front of and touching the mouth of the side-pipe 6 

 in Fig. 124. As before, several fruit-bodies in succession were 

 caused to puff into the mouth of the test-tube a. As each puff took 

 place, I heard the hiss and saw the lower end of the strip of tissue- 



FiG. 124. — Apparatus, seen from above, as used for demonstrating that a fruit-bodj' 

 of Sarcoscypha prolracta, when it puffs, produces a blast of air : a, a test-tube 

 with an open side-pipe b (shown in section at c), held in a horizontal plane by the 

 clamp e which is attached by the clamp d to the vertical rod of an iron stand ; 

 / gr, a cardboard screen ; h, a fruit-body removed from a Petri dish and placed 

 at the mouth of the test-tube about three seconds ago. The fruit-body has 

 just puffed. The million or more spores and sap-droplets which were shot into 

 the tube have impinged upon the air and set it in motion, thus producing a blast 

 of air which is now emerging horizontally through the mouth of the pipe b and 

 bearing the spores with it, as shown at i. The cup of the fruit-body is some- 

 what smaller than the mouth of the test-tube ; so that, as the air is driven 

 forward in the body of the tube a, more air enters at the mouth of the tube near 

 h. The column of spore smoke, i, was observed in bright daylight against 

 a black back-ground. Natural size. 



