106 Journal of Agricultural Research voi. vn, no . 3 
From what we know about the relative surface tensions of nicotine 
solutions, of kerosene, and of various emulsions, it is easily understood 
why kerosene and the emulsions are able to pass into the tracheae while 
the nicotine solutions can not. 
2.—tracing nicotine: as a stomach poison to tissues 
To obtain material for tracing nicotine as a stomach poison to the 
tissues and to determine the effects of an extremely small amount of 
nicotine and of indigo-carmine on bees, the following experiments were 
performed: 200 drops of pure honey were put into a feeder; 200 drops 
of honey mixed thoroughly with 40 drops of water colored blue with 
indigo-carminh were poured into a second feeder; 200 drops of honey 
mixed thoroughly with 40 drops of pure nicotine solution (1:500) 
colored blue with indigo-carmine were poured into a third feeder. Each 
of these feeders, with its contents, was placed inside an observation 
case, and 50 worker bees were introduced into each case. Before all 
the bees died nearly ail the food had been eaten. Since bees confined 
in observation cases can not void their feces, the abdomens of these 
bees became much distended with the blue-green food. The bees that 
ate the pure honey lived eight days, on an average, while those in the 
two other cases lived about seven days, on an average, showing that the 
extremely small amount of nicotine did not affect their longevity, 
whereas the indigo-carmine seemed to shorten their lives by one day. 
The preceding experiments in feeding bees nicotine and indigo-carmine 
were repeated; and three days later, when several bees showed signs of 
dying, they were placed into absolute alcohol for two days. The anterior 
portions of their abdomens, and occasionally the base of a leg, appeared 
blue-green from the outside. When cut open under absolute alcohol, 
all the tissues in the abdomen appeared blue-green. A closer examina¬ 
tion, however, showed that the alimentary canal was blue, while the 
other tissues in the abdomen as a rule were pale blue-green, with now 
and then darker colored streaks running through them. A few muscle 
fibers and some parts of the chitin were pale blue, and other parts of 
the chitin were pale blue-green. Under alcohol the tissues in the thorax 
and head did not appear colored at all; but after being removed from 
the alcohol and dried, they assumed a pale blue-green color, and occa¬ 
sionally darker colored blue streaks were seen in the muscles and brain. 
It seems that the indigo-carmine had colored the blood or body fluid 
pale blue-green and that this fluid in turn had colored all the tissues, but 
the stain was diluted too much to be “precipitated,” except in a few 
organs. 
Parts of the alimentary canal and various tissues were dissected out, 
and sections were made of them. Sections through the anterior and 
middle portions of the honey stomach failed to show any blue “precipi- 
