GENERAL SUMMARY 265 



En pure oxygen fruit-bodies shed their spores for several hours at the same 

 rate as in air. 



When a fruit-body is subjected to the vapour of ether or chloroform, 

 spore-discharge ceases almost instantaneously, but can be resumed when 

 the anaesthetic has been removed. A fruit- body of Lentites hetulina re- 

 covered its spore-liberating function after this had been inhibited by ether 

 vapour for a week. 



Chapter XI. — The four spores on each basidium are discharged suc- 

 cessively. They leave the sterigmata within a few seconds or minutes of 

 one another. 



Each spore is shot out violently from its sterigma to a distance of about 

 y 1 ^ mm. 



Chapter XII. — The propelling force during spore-discharge seems to 

 be provided by the pressure of the cell-sap of the basidium upon the cell- 

 wall, and possibly by a similar pressure in the spore. On the discharge 

 of a spore, the sterigma breaks across but does not open. Spore-discharge 

 in the Hymenomycetes appears to resemble that in Empusa Grylli, and 

 may be said to be brought about by a jerking process, which may be con- 

 trasted with the squirting process of Emyusa muscse and the Ascomycetes. 



Chapter XIII. — The specific gravity of spores can be determined 

 approximately by using heavy fluids contained in a counting apparatus, 

 the chamber of which is - l mm. deep. The specific gravity of spores of 

 Amanitopsis vaginata was found to be nearly that of water, namely, 1*02, 

 whilst that of the much heavier Coprinus plicatilis spores proved to be 

 approximately 1*21. 



Chapter XIV. — The size of spores can be measured with accuracy and 

 rapidity by using a Poynting Plate Micrometer. The apparatus has been 

 described. 



The average size of the spores of a fruit-body may differ considerably in 

 different fruit-bodies of the same species. This fact may well account for 

 the want of agreement of spore measurements as given by different 

 mycologists. 



Chapter XV. — The rate of fall of spores in still air was determined for 

 the first time. A small piece of a fruit-body was placed in a vertically- 

 disposed compressor cell. The falling spores were observed with a hori- 

 zontal microscope and their rate of fall accurately recorded upon a revolving 

 drum. 



The first direct test of the applicability of Stokes' Law to the fall of 

 microscopic spheres in air has been carried out by determining the size, 



