M. C. Lea—The Latent Photographie Image. 51 
first; after drying, the silver solution. Finally the sheets 
were very thoroughly washed out, to remove every trace o 
excess of silver nitrate and of all other soluble matter. To 
this careful washing much importance attaches. If any coc- 
culus were left in the paper, it might, by dissolving out in the 
developing solution, confuse the result, inasmuch as cocculus 
with potash exhibits some developing powers. Every trace of 
it was therefore removed by the most careful washing, and as 
an additional precaution, the most important results were re- 
peated on paper prepared with haloids only, in order to control 
the conclusions with exactness, 
Resutts.—A. Sugars. 
€ image produced by mannite is of a redder shade than 
that resulting from any other developing agent. 
B. Glucosides. 
Daphnin gave a moderately strong image; its derivative, 
Daphnetin, a bolder and fuller. Phioridzin and glycyrrhizin 
turnings gave a moderately strong one, doubtless by the con- 
version of quercetin into quercitrin. Accordingly an infusion of 
white oak bark was found to give a good image. olanin . 
