Oct. 16,1916 
Effects of Nicotine as an Insecticide 
107 
tate” either in the lumen or in the walls of this organ, but sections 
through the posterior portion of the honey stomach and other parts of 
the alimentary canal distal to the honey stomach usually showed more 
or less blue “precipitate.” There was no difference in distribution of 
the stain, whether or not it contained nicotine, but since the distribu¬ 
tion of nicotine only is of interest, the discussion will be confined to the 
distribution of the stain which formerly contained this insecticide. 
Plate 2, figure D, represents the blue “precipitate” as seen in the 
wall of the lower portion of the honey stomach. The stain seemed to 
have united with the alcohol as the former was passing through the 
chitinous layer {chi) of this organ. A little “precipitate” was also seen 
in the muscular layer {m) of this organ. 
Sections through the anterior portion of the valve of the proven- 
triculus show small particles of “precipitate” in the muscles (Pi. 2, fig. 
E, w), epithelial cells (ep), and tracheae ( tr ). 
Sections through the ventriculus show “precipitate” in various places 
of the epithelium, indicating that the stain was in the act of passing 
through the wall when it was overtaken by the alcohol. From the loca¬ 
tion of the blue “precipitate” some of the stain was just ready to pass 
into the inner ends of the epithelial cells, while some had just entered 
these cells (Pi. 2, fig. A, pr). Other portions of the stain were “pre¬ 
cipitated” midway between the inner and outer walls of the epithelium 
(Pi. 2, fig. B, pr), while still other portions were overtaken by the alco¬ 
hol when they were passing through the outer wall of the epithelium 
(Pi. 2, fig. C, pr ). At this location a small amount of “precipitate” 
was also seen in the transverse muscular fibers (PI. 2, fig. C, tm), indi¬ 
cating that, while most of the stain passed between the muscular fibers, 
some of it passed into and probably through the fibers. 
At only one place was blue “precipitate” (PI. 2, fig. H, pr) observed 
in the blood (bl). This was seen a short distance from the ventriculus 
near a small trachea (tr) and two Malpighian tubules {mat), which also 
contain a little “precipitate.” Two particles of this “precipitate” are 
lying in the outer walls of these tubules, indicating that the stain was 
passing into these organs when it was thrown down. It was also 
observed that the trachea contained several small particles of “precipi¬ 
tate.” 
Many of the Malpighian tubules, particularly those near the honey 
stomach, small intestine, and rectum, showed no traces of the stain, 
while those near the ventriculus contained a small amount of it, as repre¬ 
sented in Plate 2, figure H, and whereas those against the ventriculus 
contained large amounts of the “precipitate,” as represented in Plate 2, 
figure G. 
The “precipitated” particles in sections through the middle of the 
ventriculus are more numerous and more compact than in sections 
through either end of this organ. These sections are never perfect, 
