162 THE MICROSCOPE. Dec 
actinic, thatis to say mono-chromatic. I place between it 
and the source of light, kerosene or sunlight, and the 
condenser, a film of glass which is rendered actinie by 
having color washed on it and rendered fixed by means 
of varnish, which may be shellac, gold size, gelatin, gum 
thus oranything. Bet the varnish does not signify as 
the actinism is got by rendering it colored by blue,—one 
of the so called aniline blues of commerce that are sold 
now everywhere and are employed for dyeing. These 
blues go by various names but they are all the same. 
The film colored blue thus cuts off all the other rays that 
may be present in the source of light and renders it one 
color, darker or lighter as the case may be. The light 
is then converged by a common plano-convex lens of 
about six inches focus to the object and I find it is effi- 
cient and thoroughly actinic. There are ways for render- 
ing the light achromatic and actinic. Or simpler still, 
the film of glass colored by blue varnish is done away 
with and a solution in water of aniline blue is used ina 
glass bottle with parallel sides. In this manner the 
iight can readily be rendered actinic and the solution can 
be stronger or less strong with blue as seems necessary. 
Discontinued.— We regret to announce that the Inter 
national Journal of Microscopy and Natural Science, 16 
years old, discontinued in October. The Observer of 
Portland. Conn., has also ceased to be published after six 
years of struggle. We are informed that the Journal 
of the Royal Microscopical Society is in a bad way and li- 
able togo under at any time. ‘This perodical of ours will 
also fall into the line. ‘The 18 year old American Monthly 
will go on for the present. 
Physicians who use electricity should send to Wm. F. 
Howe, M. D., Indianapolis, fora sample of The Electro- 
Therapeutist a monthly devoted to the subject. 
