488 
but of a widely different class from the mallow, in which the vein- 
ing is prominent and the work of a leaf miner is illustrated, as 
also the presence of a blight (Pyl/ostica cruenta, Fr.) following in 
the wake of the ruin caused by the insect and producing its fruit- 
ing pycnidia. 
By this process there is no opportunity for any minifying or 
magnifying of the object, and each detail is as exact as to size, 
location, etc., as possible. But the strongest pvints in favor of the 
process, aside from the merits of the results, are the ease with 
which the picture may be taken by any one, and the remarkable 
cheapness, for no camera or dark room is needed, and the whole 
time for the first exposure of the object until the positive is fin- 
Fic. 2.—LraF OF Polygonatum biflorum with Leaf-Miner, followed by 
Phyllosticta cruenta, FR. 
ished may not be more than three hours. 
There is nothing new in sun-printing, for Professor Kellerman 
and other American botanists have employed it. The chief point 
to be urged is the use of the clarifying agent, kerosene, for sub- 
jects when they are dry and for negative prints. This not only 
diminishes the time of exposure ten fold and more, but remark- 
ably sharpens the details of the positive picture. 
Byron D. HALsTED. 
RuTGERS COLLEGE, November 13, 1893. 
