46 RESEARCHES ON FUNGI 



not observed for 36 hours, but the length of time required for their 

 development was estimated by a sufficiently reliable comparative 

 method, the nature of which will be explained in Volume III in 

 connection with a discussion of the development of the hymenium. 1 



Where a gill was comparatively thin and translucent (Stropharia 

 semiglobata, Collybia, velutipes, etc.), just sufficient light passed 

 through its whole substance to permit of spore-development being 

 observed anywhere on the hymenium covering the upper side of 

 the gill. However, to watch the four spores on a particular 

 basidium projecting upwards to the eye, from their first origin to 

 their discharge, by a dim light, and for several hours with but 

 short occasional breaks, is somewhat tedious work and rather 

 trying for the eyes ; and one may be pardoned perhaps, if, when 

 one's vigil of watchful waiting has at length been brought to a 

 successful close by the dramatic shooting off of the four microscopic 

 projectiles, one's pleasure is mixed with a feeling of relief. When a 

 gill was comparatively thick and but feebly translucent (Marasmius 

 oreades, Collybia radicata, Hygrophorus ceraceus, etc.), it became 

 necessary to turn one's attention to the basidia projecting freely 

 from that edge of the gill which normally looks down toward the 

 earth. Under these conditions the basidia and spores were observed 

 in lateral view. 



The fruit-bodies of Exidia albida and of Dacryomyces deliquescens 

 were cut in half ; one half was laid with its plane of section more 

 or less in contact with the base of the compressor cell ; a drop of 

 water was added ; the compressor cell was closed ; and then the 

 basidia and spores were observed in lateral view with the low 

 power of the microscope. 



The question arises whether or not the gills or parts of fruit- 

 bodies placed in the compressor cell continued to develop their 

 hymenium normally. In my opinion the answer, for all the species 

 named in the Table, must be in the affirmative. By experience, 

 one becomes used to normal spore-development, which is charac- 

 terised by great regularity in the rate of increase in size and, where 

 the spore- walls become pigmented, in the rate of pigmentation, 

 and also characterised by the excretion of a drop of water of a 

 1 Vol. iii, Chap. Ill, section : " The Structure and Development of the Hymenium." 



