88 RESEARCHES ON FUNGI 



tubes, 8 inches high and 1 • 5 inches wide, were half -filled with fresh 

 horse-dung balls and plugged with cotton-wool. The tubes were 

 then sterilised in a steam steriliser by heating them on three suc- 

 cessive days for one hour at a temperature of 100° C. Each tube 

 was then inoculated by removing its plug and holding above its 

 mouth, for from 15 to 30 seconds, a pileus of Coprinus sterquilinus 

 which was actively shedding spores. The plug was then replaced 

 and the tubes were kept at laboratory temperature. The inocula- 

 tion was carried out in a large damp-chamber, the air of which was 

 presumably free from bacteria. In the course of a few days the 

 mycelium of the fungus began to develop in each of the tubes and, 

 after a few weeks, fruit-bodies made their appearance and came to 

 maturity. There is no reason to suppose that any bacteria entered 

 the tubes during the process of inoculation or that any living bacteria 

 were left in the dung after its final hour in the steam steriliser. 

 In regard to the latter part of this statement, it may be added that 

 it was found by plating out with nutrient gelatine that, while one 

 application of heat for one hour at 100° C. does not completely 

 sterilise fresh horse-dung balls, sterilisation is accomplished by a 

 second similar application of heat given after an interval of 48 hours. 

 In the Winnipeg laboratory, passing observations made (1) by 

 Miss Mounce whilst studying the homothallism of Coprinus sterqui- 

 linus and (2) by Hanna whilst studying the inheritance of spore 

 size in C. sterquilinus have completely confirmed the observations 

 of Churchward and the writer ^ recorded above. In the course of 

 their work, Miss Mounce ^ and Hanna ^ made numerous mono- 

 sporous cultures of C. sterquilinus, and the germination of the 

 spores in the culture medium free from bacteria and other organisms 

 was a sine qua non for the success of their experiments. Hanna, 

 employing the dry-needle method, sowed 433 spores of various 



^ The experiments on Coprinus sterquilinus made by Churchward and the 

 writer, here recorded, were completed in 1915 ; but, owing to the war, their publica- 

 tion has been delayed until now. 



2 Irene Mounce, " Homothallism and the Production of Fruit-bodies by ]Mono- 

 sporous Mycelia in the Genus Coprinus," Trans. Brit. Myc. Soc, vol. vii, 1921, 

 pp. 198-217 ; also " Homothallism and Heterothallism in the Genus Coprinus," 

 ibid., 1922, pp. 256-269. 



3 W. F. Hanna, " The Inheritance of Spore Size in Coprinus sterquilinus,"' 

 Trans. Brit. Myc. Soc, vol. xi, 1926, pp. 224-225. 



