314 



Mycologia 



pictures to the stone. When tri-color printing came, these two 

 possible sources of error were reduced to one, namely to the 

 artist's original painting. Yet, it must be stated, though we 

 gained in the objective rendering of a colored original through 

 the use of the tri-color process, we also lost very materially, and 

 this for two reasons. 



First, tri-color printing, in order to counteract a certain dulling 

 of colors 4 inherent in the process, sometimes employs highly 

 fugitive coal-tar dyes. Secondly, in order to obtain the best re- 

 sults in printing, the surface of the paper must be extremely 

 white and smooth, qualities that are secured by applying a coat 

 of chalk. When one considers these two serious handicaps, it 

 becomes a question whether this otherwise commendable process 

 should be employed in reproductions that are to adorn works of 

 high scientific value. We use and enjoy today the illustrated 

 books of our predecessors who printed with comparatively safe 

 colors on most enduring paper: our successors, centuries hence, 

 will, I fear, have no such permanent, pictorial records of the 

 work done by ourselves. 



The other processes commonly used today in the reproduction 

 of drawings and photographs, the zinc and copper line-engraving, 

 the half-tone, and the heliogravure, need not detain us as all are 

 familiar with the results. Of the two processes, however, the 

 half-tone and the heliogravure, the former is much the less dur- 

 able, for the reason that, as in the tri-color process, chalk-coated 

 paper is usually the surface for the print. The mesh, present in 

 all half-tone reproductions, may also be urged as an objectionable 

 feature when a hand-lens examination for morphological details 

 becomes desirable (PI. 26). As examples of most satisfactory 

 reproductions of photographs of fungi, the heliogravures issued 

 a few years ago by the late Prof. E. T. Harper may be cited 

 (1913, 1914a, b, 1916). 



Let us now take a glance at the principal fungus-works of the 

 past three hundred years. The very early herbalists paid little 

 attention to the fungi, merely repeating what we find in the 

 * The blue and yellow colors, being complementaries, make a gray-green 

 rather than a pure green. 



