- 513 - 
Eggs in all stages of development were "brushed with nicotine 
sulphate solutions of known strengths . A concentrations equiva- 
lent to 0.03 percent pure nicotine destroyed all eggs, whereas 
more dilute solutions killed the older ones only, the younger "being 
merely retarded in development. It was found that the toxic action 
occurs when the fully developed nerves and tracheae "begin to function, 
death "being due to nicotine vapor inhaled through the egg shell. In 
another set of tests, eggs were placed in Dottles in which pure nico- 
tine was evaporated. A dose of 0.2836 mg. per 1. killed all eggs 
except those less than 24 hours old. TTlth smaller doses, all eggs 
survived. 
RICHARDSON, C H., and HAAS, L.E. (2173) 
1932. THE RELATIVE TOXICITY OF PYRIDINE AND NICOTINE IN THE GASEOUS 
CONDITION TO TRLB0LIUI1 CONFUSUM DUVAL. Iowa State Coll. Jour. Sci . 
5 (3): 287-298, illus. [Abstract in Rev. Appl • Ent. (A) 21: 421. 
1933.] 
Nicotine was on the average about 31 times as toxic as pyridine, 
causing 50 percent mortality in 360 minutes at a concentration of 
0.228 mg. per 1. and in 133 minutes at 0.42 mg. , whereas the corresponding 
figures for pyridine were 8.8 and 12.9 mg. 
YABUTA, T., and KGZU, T. (2174) 
1932. TOXIC SUBSTANCE IN MULBERRY LEAVES DAMAGED 3Y TOBACCO. TOXIC 
ACTION OE NICOTINE AND mMSTHYLAMINE ON SILK T70RI.1S . Jour. Agr. Chem. 
Soc. Japan 8: 770-775. [Abstract in Chen. Abs. 27: 2220. 1933.] 
The symptoms of poisoning "by nicotine and trimethylamine in silk 
worms were compared. The toxic substance in damaged mulberry leaves 
seems to "be nicotine. 
O'KANE, n. C, TALKER, G. L., GUY, H. G-, and SMITH, 0. J. (2175) 
1933. STUDIES OE CONTACT INSECTICIDES. VI. 1. REACTIONS OE CERTAIN 
INSECTS TO CONTROLLED APPLICATIONS OE VARIOUS CONCENTRATED CHEI.1ICALS, 
2. A NET7 TECHNIQUE NOR INITIAL APPRAISAL OE PROPOSED CONTACT INSECT- 
ICIDES. IT. H. Agr. Expt. Sta. Tech. Bull. 54, 23 pp., illus. [Ab- 
stract in Rev. Appl. Ent. (A) 22: 74-75- 1934.] 
Tests were made of the sensitiveness of different parts of 
the larvae of Tenebrio molitor L. and cockroaches to minute drops 
of nicotine. 
TU1LC0X0IT, E., and HART ZELL, A. (2176) 
1933. SOME EACTORS AFFECTING THE EFFICIENCY OF CONTACT INSECTICIDES. Ill 
FURTHER CHEMICAL AND TOXICOLOGIC^ STUDIES OF PYRETHRUM. Contrib. 
Boyce Thompson Inst. 5 (l): 115-127, illus. [Abstract in Rev. Appl, 
Ent. (A) 21: 192-193. 1933.1 
