i8o 



RESEARCHES ON FUNGI 



The faeces of horses always contain, in addition to innumerable 

 bacteria, the spores of a number of coprophilous fungi. These spores 

 have been swallowed with the fodder and, notwithstanding their 

 passage through the alimentary canal of the animal concerned, have 

 retained their vitality. When, therefore, the dung-balls freeze in 

 the streets of Winnipeg, the spores of various coprophilous fungi 

 which are included in them freeze up too. It was found that, if 

 frozen dung-balls such as those just described are collected from 

 the streets at any time during the winter, brought into the 



Fig. 69. — Coprinus sterquilinus. Two fruit-bodies in a very early stage of develop- 

 ment, growing on sterilised horse dung. White mycelium is to be seen on the 

 surface of the dung. Each fruit-body consists of a stipe which is swollen 

 below, and of a conical pileus. Natural size. 



laboratory, and placed in a covered crystallising dish, in the course 

 of a few weeks they always give rise to fruit-bodies of one or more 

 small species of Coprinus, of which Coprinus curtus, C. ephemerus, 

 and C. lagopus are the commonest. Sometimes, however, they 

 give rise to the relatively large fruit-bodies of Coprinus sterquilinus. 

 It is always possible to know whether or not a dung-ball which 

 has been kept a few weeks is going to produce a fruit-body of this 

 fungus ; for, if it is, a white floccose layer of mycelium first appears 

 on the outside of the dung-ball in such a way as to cover the ball 

 in part or as a whole (c/. Figs. 69, and 71, p. 182). Further, if 

 several adjacent dung-balls are infected, thick white strands are 

 developed which connect the mycelium of the different balls together. 

 One dung-ball seldom gives rise to more than one fruit-body, and 



