120 
Journal of Agricultural Research 
Vol. VII, No. 3 
SUMMARY . 
(1) Nicotine spray solutions do not pass into the tracheae, nor do they 
penetrate the integuments of insects. 
(2) The fumes from nicotine used as a fumigant, the vapors from 
nicotine spray solutions, and the odoriferous particles from evaporated 
nicotine spray solutions or from powdered tobacco pass into the tracheae 
and are widely distributed to all the tissues. 
(3) Regardless of how it is applied, whenever nicotine kills insects, 
as well as all other animals, it kills by paralysis, which in insects travels 
along the ventral nerve cord from the abdomen to the brain. 
(4) The writer does not know just how nicotine paralyzes the nervous 
system, but he does know that it prevents the nerve cells from function¬ 
ing, and that in regard to the simplest animals its presence around the cells 
causes the same structural changes resulting in death as observed when 
other animals of the same kind are deprived of oxygen. In such cases 
it seems to kill physically rather than chemically, but the evidence 
presented does not conclusively prove this view. In the higher animals 
it may kill by interfering with oxidation in the cells; whether this is 
accomplished physically or chemically the writer does not know, but con¬ 
cluding from the properties of nicotine he is inclined to attribute more 
to its physical effects than to its chemical effects. 
LITERATURE CITED 
(1) AutEnriEth, Wilhelm. 
1915. Laboratory Manual for the Detection of Poisons and Powerful Drugs. 
Ed. 4, translated by W. H, Warren. 320 p., 25 fig. Philadelphia. 
(2) Baker, A. C. 
1915. The woolly apple aphis. U. S. Dept. Agr. Office Sec. Rpt. 101, 55 p., 
3 fig., 15 pi. Literature referred to in the text, p. 53-55. 
(3) Beyth, A. W. 
1895. Poisons: their Effects and Detection. Ed. 3, 724 p., illus. London. 
(4) Brundage, A. H. 
1910. A Manual of Toxicology ... Ed. 7, 428 p., illus., pi. New York, Lon¬ 
don. 
(5) BudgETT, S. P. 
1898. On the similarity of structural changes produced by lack of oxygen and 
certain poisons. In Amer. Jour. Physiol., v. 1, no. 2, p. 210-214, 
9 fig- 
(6) Cushny, A. R. 
1915. A Text-Book of Pharmacology and Therapeutics ... Ed. 6, 708 p., 70 
fig. Philadelphia, New York. 
(7) DEwitz, J. 
1912. The bearing of physiology on economic entomology. In Bui. Ent. 
Research, v. 3, pt. 4, p. 343-354. Bibliography, p. 352-354. 
(8 ) Fischer, Alfred. 
1899. Fixirung, Farbung und Bau des Protoplasmas. 362 p., 21 fig., 1 col. pi. 
Jena, Literatur, p. 341-348. 
