ORGANIC AND INORGANIC MATTER COMPARED. 87 



comprehend not only mushrooms, toadstools, 

 puff-balls, and similar productions, but also a 

 large number of microscopic plants, forming 

 those appearances "which are referred to in 

 popular language by the words mouldiness, 

 mildew, smut, brand, dry-rot, etc. 



Nothing can well be more different than the 

 extremes of development presented by fungi, if 

 we contrast the largest forms with microscopic 

 species ; the large fleshy Boleti, for example, 

 which grow on the trunks of decaying trees, 

 and the mould-plants, composed of threads too 

 delicate to be distinguished by the naked eye. 

 Investigation, however, has clearly demon- 

 strated that the latter is only a simple phase or 

 type of the former, and that a huge, firm, 

 leathery boletus is merely an enormous aggre- 

 gation of the fine vegetable tissue constituting 

 a mould-plant or mucor. In each is the same 

 plan of development, the same chemical charac- 

 ter, and the same mode of propagation. Taking 

 a general view of the fungi, the assemblage of 

 plants included under this term may be de- 

 scribed as cellular or filamentous bodies, 

 having a concentric mode of development, and 

 propagating either by means of microscopic 

 granules or seeds, called spores, or by a disso- 

 lution of their whole tissue. Contrary to the 

 normal law of plants, they absorb oxygen and 

 exhale carbonic acid. 



That these plants consist of a cellular or 

 filamentous tissue may be easily ascertained 

 by means of a microscope of even moderate 



