1896.1 on the Circulation of Organic flatter. 165 



sheath are dead cells in tLe root cap which remain held in the fungal 

 matrix. 



All animals appear to be symbiotic, for we all carry about millions 

 of microbes which must fairly be regarded as junior partners in our 

 economy, and which we cannot do without. The microbe which has 

 been chiefly studied — the Bacterium Coli commune — apj)ears to be 

 essential for certain digestive processes which go on in the intestines 

 while we live ; and when we die this microbe is active in starting the 

 dead body upon that cycle of events which is one form of the " Circu- 

 lation of Organic Matter." 



Now it is certain that the dung of all animals swarms with bacteria 

 and allied organisms when it leaves the intestines, and it seems highly 

 probable that excrement carries with it the biological machinery which 

 is necessary for its dissolution and ultimate humification. 



My friend, Mr. George Murray, the keeper of the Botanical De- 

 partment of the British Museum, whose learning in fuugology is well 

 known, has kindly furnished me with an elaborate list of 139 genera 

 of fungi which flouiish on excrement. 



Of these 139 genera Mr. Murray has tabulated no less than 628 

 species wliich are known to flourish on excrement. 



Of the 628 species 226 have been found on the dung of more than 

 one genus of animals, but no less than 402 species of fungi are 

 peculiar to the excrement of only one genus of animals. 



Of these 402 S23ecies of fungi 91 are peculiar to the dung of the 

 ox; 78 to the horse; 68 to the hare and rabbit; 30 to the dog; 25 

 to the sheep ; 28 to birds ; 21 to man ; 16 to the mouse ; 9 to the deer; 

 7 to the pig ; 7 to the wolf, and 22 to other animals. 



This marvellous list is on the table for the inspection of those 

 who are learned in such matters. 



This search for fungi in excrement is necessarily incomplete. In 

 Mr. Murray's list it is evident that the greatest number of species 

 have been found in the dung of animals which are domesticated and 

 common, and which offer facilities to the fungologist. The numbers 

 are startling, but when we consider that the dung of every living thing 

 which crawls or burrows, or swims or flies, has properties which are 

 peculiar to it, and which fit it to become the nidus of some peculiar 

 fungoid or bacterial growth, the part played by fungi in the distri- 

 bution and circulation of organic matter cannot be over-estimated. 



The facts which have been recounted, and which seem to show that 

 fungi and bacteria are necessary for the growth and development of 

 even the highest plants and animals, and that fungi and animals are 

 equally necessary for the dissolution of organic matter, seem to point 

 to the conclusion that the correlation of the biological forces in this 

 world is no less exact than the correlation of the physical forces. The 

 uniform composition of the atmosj^here, except under special and 

 local conditions, is a fact which points in the same direction. 



