JOURNAL OF AdlllLTlAI, BEAM 
DEPARTMENT OF AGRICULTURE 
Vol. VII Washington, D. C., October 16, 1916 No. 3 
EFFECTS OF NICOTINE AS AN INSECTICIDE 
. By N. E. McIndoo 1 
Insect Physiologist , Deciduous Fruit Insect Investigations , Bureau of Entomology 
INTRODUCTION AND EXPERIMENTAL METHODS 
The pharmacological effect of nicotine (C 10 H 14 N 2 ) on the higher animals 
is well understood, but there is practically nothing known about the 
pharmacological effects of nicotine as an insecticide. Owing to the 
high cost of nicotine, it is desirable to have a substitute for this insecticide. 
Before being able to discover, if possible, such a substitute, it is first 
necessary to ascertain how nicotine affects insects. 
In the investigation herein recorded two chief objects have been 
kept in view: (1) To determine the physiological effects of nicotine as 
an insecticide, and (2) to trace the nicotine into the insects after it 
has been applied to them. A brief account of the pharmacological 
effects of nicotine on other animals and the views pertaining to the 
physical and chemical effects of nicotine on the cells are also given. 
Owing to the small size of the insects utilized in the experiments the 
usual method of procedure employed by pharmacologists could not be 
used, because it was impossible to operate on living insects in order to 
ascertain what tissue is vitally affected by nicotine. Consequently the 
behavior of the insects treated with nicotine was compared with the 
behavior of normal and untreated ones; and immediately after the 
treated ones had died, they were fixed in a fluid containing a nicotine 
precipitant. By this means the nicotine was precipitated wherever it 
had gone into the insects; and after making microscopical sections from 
these insects, it was not a difficult task to trace the precipitated nicotine. 
Shafer (20, 21), 2 from the standpoint of a physiological chemist, carried 
on investigations to determine how contact insecticides kill. He did not 
1 The writer is grateful to the following persons: To Mr. A. F. Sievers, Chemical Biologist in Drug-Plant 
and Poisonous-Plant Investigations, for extracting pure nicotine from a commercial nicotine material 
and for verifying the percentage of nicotine in a sample of 40 per cent nicotine sulphate; to Dr. D. E. 
Jackson, of the Department of Pharmacology, Washington University Medical School; and to Mr. O. D. 
Swett, Assistant Professor of Chemistry in George Washington University, for reading and criticizing 
the manuscript of this paper. 
2 Reference is made to Literature cited, pp. 120121. 
* Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C., 
fr 
Vol. VII, No. 3 
Oct. 16, 1916 
K—43 
(89) 
