Page:Popular Science Monthly Volume 29.djvu/452

436 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 structure 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, destitute 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 return 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 beginning 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 Schizomycetes, 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