COPRINUS STERQUILINUS 



207 



was grown in the laboratory on horse dung under a bell- jar. In 

 course of time its pileus became barrel-shaped and attained a stage 

 of development which experience had taught me normally precedes 

 the spore-discharge period by about 36 hours (c/. 

 Fig. 70, p. 181). A small block of tissue (Fig. 

 88, A), about 6 mm. high, just sufficiently large 

 to be held comfortably in the fingers for section- 

 cutting with a razor, was thereupon removed from 

 the base of the pileus with the help of a sharp 

 scalpel, care being taken to do as little damage as 

 possible to the fruit-body so that its development 

 might continue in a normal manner. Sections were 

 then made with a hand-razor from the upper surface 

 of the block of tissue, several gills being cut through 

 transversely at a distance of 5-6 mm. above their 

 extreme lowest points at the basal rim of the pileus. 

 Thereafter, at the same height above the rim of the 

 pileus and at successive intervals of time, similar 

 sections were taken from a series of blocks of 

 tissue (B, C, etc., in' Fig. 88) cut away from the base 

 of the pileus in a similar manner to the first block. 

 The sections taken from all the blocks were com- 

 pared and thus the rate and mode of development 

 of the hymenium was worked out. It will thus be 

 seen that the method of obtaining sections and 

 making comparative observations from them, as 

 just described, is based on the fact that all the 

 gills develop in an equal manner, in that a single 

 wave of hymenial development passes upwards on 

 all the gills simultaneously from the base of the 

 barrel-shaped pileus to its apex. The sections were 

 all mounted in water and studied in the living condition immediately 

 after they had been cut. 



The section sketched in Fig. 89, A, was made from a block of 

 material removed from the pileus at 5 p.m. As already pointed out, 

 it shows that the long basidia, the short basidia, and the paraphyses 

 are all clearly differentiated from one another ; but that the basidia 



Fig. S8.—Copri- 

 nus sterquilinus. 

 A young fruit- 

 body j ust before 

 the de V e 1 o p - 

 nient of sterig- 

 m a ta and 

 spores. A, B, 

 C, etc., blocks 

 of tissue which 

 were removed 

 at successive in- 

 tervals of time 

 and from the 

 tops of which 

 transverse sec- 

 tions were cut 

 for the purpose 

 of studying the 

 rate of develop- 

 ment of the 

 sterigmata and 

 spores. Natural 

 size. 



