RELATIVE SUSCEPTIBILITY TO ARSENIC IN SUCCESSIVE INSTARS OF THE SILKWORM
The susceptibility of the silkworm to arsenic decreases during its larval development. Relative susceptibility may be expressed numerically as a ratio of areas under dosage-effect curves.
A technique for determining the stomach poison effect of insecticides used against leaf-eating insects.
Methods devised for feeding individual insects with leaf areas bearing known deposits of insecticides are described, and the problems associated with incomplete consumption of the treated leaf portions are discussed. An account is given of the difficulties of applying the technique to small insects and to those with erratic feeding habits. 
 
 
 
Experimental data are given to illustrate the effects on insect resistance of the following: (i) rearing conditions, (ii) larval age and body weight, (iii) acute and chronic poisoning, (iv) the diluting effect of the leaf tissue consumed with the poison dose. 
 
 
 
The dosage mortality curve for stomach poisons was found to be typically sigmoid: analysis of results by the method of probits (Bliss, 1934) therefore proved satisfactory. Using lead arsenate against fifth-instar larvae of Phlogophera meticulosa the ratio of weight increase to increase in median lethal dose was found to be constant.
Industrial inorganic pigments
General Chemical and Physical Properties Behavior of Pigments in Binders White Pigments Titanium Dioxide Zinc Sulfide Colored Pigments Oxides and Hydroxides Cadmium Pigments Bismuth Pigments Ultramarine Pigments Iron Blue Pigments Carbon Black Properties Production Processes Specialty Pigments Magnetic Pigments Anticorrosive Pigments Luster Pigments Transparent Pigments.