436 THE POPULAR SCIENCE MONTHLY. 



through the entire year. In the spring of 1876 I laid out a short log- 

 railroad in the Michigan forests. The cut of the company for that 

 year was 8,000,000 feet, board-measure ; for 1886 it will be 120,000,- 

 000 feet, largely to supply the Atlantic coast with white-pine lumber. 



Timber cut in the spring growth, when the starch in the sap-wood 

 is transforming, furnishes in this part of the wood a good media for 

 the growth of various ferments which produce decomposition in such 

 products, and unless quickly checked will start the decay of the woody 

 tissue. 



It was the universal belief, until a few years since, and is still a 

 common one, that the decay of timber was due to Eremacausis slow 

 combustion. It is to the improvement and use of the microscope and 

 its accessories, that the true causes of decay of wood, are found to 

 be due to various forms of fungi. Many definite forms which cause 

 fermentation have been traced and more are known to exist which 

 are beyond the definition of present microscopes, unless they can be 

 stained so as to differentiate them. Photo-micrographs, which give 

 indications of structure far beyond what the eye can recognize, are 

 important aids in this study, while the details they give of the struct- 

 ure of the wood could not be obtained in any other manner. 



What are the fungi ? 



A great group of a low order of leafless and flowerless plants, des- 

 titute of chlorophyl, many of them microscopic, whose functions are 

 under certain conditions to break up and liberate the compounds of 

 and in the cell-structure, formed by chlorophyl-bearing leaves in the 

 sunlight. 



In short, the functions of the growing fungi are to undo and re- 

 turn to the air and soil the elements assimilated by the higher plants 

 and trees in their woody structure during growth. 



A mycologist would give a different definition of the fungi having 

 reference to the form of fructification and spores, their functions being 

 of less importance to him ; while an epicure would only describe the 

 mushrooms which please his taste. 



It is now estimated that over fifty thousand species of fungi have 

 been described ; less than five hundred of them were known in the be- 

 ginning of the century. A great number of the species are confined 

 to special habitats, and all of them will not be found upon the 

 woods. One fungus may only be found upon one or two species of 

 wood, while others will be more general. The species we illustrate by 

 cuts belong to the highest orders, and are typical to some extent of 

 many others. Associated with these are some of unicellular structure, 

 which belong to the genus Saccharomycetes or budding fungi of 

 which the yeast-plant is typical ; and others belong to the Schizomy- 

 cetes, the fission fungi bacteria, etc. forms of which are attracting 

 so much attention in connection with diseases of mankind. 



Generally speaking, the first condition by which the higher fungi 



