90 RESEARCHES ON FUNGI 



therefore, that Miss Baden's conclusions concerning the maturation 

 of the spores of C. sterquilinus are erroneous. 



Possible Effect of Bacteria on Germination. — While, as shown 

 above, the presence of bacteria is not necessary for the germination 

 of the spores of Coprinus sterquilinus, it is yet possible that, under 

 natural conditions in pastures, the germination of the spores, which 

 always takes place in the presence of bacteria, may be affected by 

 bacterial products of metaboUsm ; but the worth of this suggestion 

 remains to be tested by actual experiment. Spores, on passing 

 down the aUmentary canal of a horse, are immersed in a medium 

 which is raised to a high temperature, are bathed for many hours 

 by the strong enzymes with which the horse digests its food and, 

 by the time that they reach the rectum, become surrounded with 

 highly nutrient food substances. Under these conditions of tem- 

 perature, enzymes, and food substances, although the oxygen 

 supply may be reduced to a minimum, it may well be that the spores 

 undergo those prehminary changes which are necessary for germina- 

 tion, so that the production of germ-tubes may begin almost im- 

 mediately the faeces are extruded as dung-balls. This seems to be 

 all the more probable, since early germination in freshly-dropped 

 horse-dung balls must, undoubtedly, be an important factor for 

 success in the intense struggle for possession of the substratum 

 which goes on among the competing fungi. 



The Struggle for the Substratum. — As bearing on the problem 

 of the struggle for the substratum, we may remind ourselves of the 

 three experiments recorded in the first Section of this Chapter. It 

 was shown that, when freshly-dropped horse-dung balls were 

 suppUed with millions of spores of Coprinus sterquilinus, this fungus 

 did not succeed in developing any fruit-bodies : it was beaten in 

 the struggle by other competing species of fungi ; it entered the 

 contest under a disadvantageous condition, namely, delayed 

 germination of its spores. In a further experiment this condition 

 was reversed. Pieces of horse dung, overspread with the vigorously 

 growing mycelium of G. sterquilinus, were placed upon some just- 

 dropped dung-balls, with the result that the myceUum spread 

 rapidly over the balls, and, in the end, gave rise to fruit-bodies. 

 Artificial priority of development had been given to C. sterquilinus 



