FIG. 91. Apparatus for observing the development of successive generations of 

 basidia and spores on a small portion of the hymenium of a gill of Panaeolus 

 campanulatus. S, a circular stand made of brass and wood, on which is resting a 

 block of wood, W. The glass dish, D, rests on the block, W, and is held in place 

 by the elastic band, VB. The dish is closed in front with the exception of the 

 small ventilating space, V, by the thick glass plate, GP, which rests on the top 

 of the stand and is held to the glass dish by the horizontal elastic band, HB. The 

 strip of thin cover-glass, Cg, is attached by a mixture of wax and fat to the inner 

 surface of the glass plate at a place where part of the plate has been broken away. 

 The dish is partly filled with three large corks. A fruit-body of Panaeolus cam- 

 panulatus has been removed from a culture and placed in the dish so that the 

 base of its stipe is covered by the wet cotton-wool, CW. The pileus, after being 

 dissected so that only one gill is left on the right-hand side, rests against the 

 side of the glass dish. The fruit-body is also fixed in a constant position by the 

 three needles stuck in the strips of cork, Ck, and by the black-headed pins stuck 

 into the two large circular corks. A is an area of the hymenium which 'was 

 observed with a horizontal microscope for three days and three nights. Reduced 

 to one-half the actual size. 



