Journal of Agricultural Research 
Vol. VII, No. 3 
118 
cornutus I?ab.) confined for 24 hours in pure hydrogen completely recover 
when placed in fresh air. These experiments indicate that nicotine does 
not kill insects merely on account of the paralysis of the respiratory cen¬ 
ters, because the tracheae and tissues of an insect contain enough oxygen to 
keep the cells alive for several hours. Since the cells of insects are con¬ 
stantly surrounded by air containing oxygen, an investigation will be 
made as to whether or not nicotine interferes with oxidation in the cells 
and whether it kills physically or chemically. 
Greenwood (9) observed that when simple animals die from the effects 
of nicotine, death is often associated with injury to the cell contents so 
that they tend to disintegrate. This is shown in the protozoan, Actino - 
sphaerium sp., and in the coelenterates, Hydra spp. and Medusa spp. 
Budgett (5) treated infusorians with a number of poisons, including 
nicotine, and found that these protozoa become strongly vacuolated and 
finally the membranes burst, allowing the protoplasm to flow out into the 
water. The same structural changes occurred when he deprived them of 
oxygen. He says (p. 214): “This indicates that either these poisons 
prevent oxidation or that lack of oxygen produces toxic substances.” 
He also believes that these poisons not only reduce the normal resistance 
to the entrance of water but lead to the taking up of water, probably by 
hastening the molecular breakdown and so increasing the osmotic pres¬ 
sure within the cell. 
Toeb (16) and others have experimented extensively with amebae and 
paramecia by depriving them of oxygen. They always observed the 
same structural changes as already cited from Budgett. Loeb also 
performed many experiments by depriving the eggs of a certain fish of 
oxygen. He exposed the eggs to a current of hydrogen and observed— 
The liquefaction of the cell walls and the formation of droplets began when the egg 
was in the 8-cell stage (Fig. 2). These droplets fuse into larger drops and finally 
nothing but these drops indicates the existence of the germinal disk. 
The present writer placed living fat cells and cenocytes of the honeybee 
on a slide in water under a cover glass. These cells live in tap water for 
some time before any changes in their appearance can be observed; 
but when a drop of pure nicotine is placed at the edge of the cover glass, 
changes in their general appearance take place soon afterwards. The 
globules in the cells sometimes dance about, resembling the Brownian 
movement. The globules in the fat cells usually soon lose their rotun¬ 
dity, become massed together, and form a coarse, granular structure. 
The refractive bodies in the cenocytes soon disappear, and then these 
cells become opaque. After considerable time the cell walls of the fat 
cells and cenocytes burst, and the cell contents disintegrate. 
In the preceding pages it is shown that either lack of oxygen or the 
presence of nicotine around simple animals brings about structural 
changes resulting in death. A comparison, although a rough one, might 
