1899] MICROSCOPICAL JOURNAL. 185 



material is ready the tube is filled with paraffin, and after 

 the spores have sunk to the bottom the whole is quickly 

 cooled. The paraffin soon hardens. The tube is then 

 broken, leaving the paraffin cast, which, with a little trim- 

 ming, is at once ready for the microtome. — Knowledge. 



General Characters of the Fungi. 



G. MASSES- 



Fungi were differentiated as a group before the evolu- 

 tion of terrestrial (dry land) vegetation, and as a combi- 

 nation of necessity, convenience, and gratitude, lived in 

 the first instance as parasites upon various members of 

 the group of plants from which they were evolved, the 

 seaweeds or algse. A small section, the conservative 

 party, have retained this habit up to the present day. 



All fungi are parasites in the sense of requiring or- 

 ganic food, some being satisfied with dead matter, others 

 attacking living organisms ; many are capable of utiliz- 

 ing with equal satisfaction living or dead matter as food. 



In primitive aquatic forms the entire fungus is buried 

 in the body of the host on which it is parasitic, the one 

 form of reproductive bodies, which are of sexual origin, 

 and closely resembling those of the ancestral algal type, 

 being liberated on the decay of the host, and dispersed 

 by water. 



The evolution of terrestrial vegetation afforded an op- 

 portunity for the extension in space of fungi ; and the 

 extent to which they availed themselves of the opportu- 

 nity may be estimated from the fact that at the present 

 day no fewer than 45,000 species of terrestrial fungi are 

 known, whose distribution is equal to that of the higher 

 forms of vegetable life on the presence of which their 

 existence depends, no fungus having deviated from the 

 primitive parasitic mode of life. 



Fossil wood from rocks belonging to tbe carboniferous 



