Toxin of Sea Hares- — Winkler 
213 
when given by stomach tube at approximately 
12 times the intraperitoneal LD 50 dose. 
Helix aspersa O. F. Muller withstood doses 
of the toxin sufficient to kill several mice with 
only temporary effects. However, the purple 
shore crab quickly went into a relaxed state 
when small quantities were injected at the po- 
dial interstices. Since they were presumed dead, 
they were not observed further. 
When frogs are injected with the LD 50 dose/ 
gm weight for mice, the dorsal appendages be- 
come weakened and paralyzed in approximately 
5 min. This is followed quickly by relaxation 
( Fig. 1 ) , complete except for the anterior limbs, 
which become spastic. The rectus abdominis is 
also tensed. The muscles controlling the eyes 
are the last to become paralyzed. A complete 
deathlike stupor follows, lasting about 15 hr. 
The first reaction to reappear is the movement 
of the nictitating membrane and retraction of 
the eyes. Soon thereafter, when teased in the 
eye region, an isolated leg twitch may occur, 
usually in the thigh region. As time progresses, 
Fig. 1. The reaction of the frog to the toxin of A. 
californica. Note the tensed abdominal muscles and 
forelegs. 
FIG. 2. The reaction of the chick to the toxin of 
A. californica. The toxin was injected subcutaneously 
over the breast. 
teasing produces an initial kick followed by 
complete immotility for a time. In 3 to 5 hr. 
more the frogs recover completely. 
Three-day-old baby chicks were injected with 
lethal doses to observe symptoms. Immediate 
hyperventilation occurred, followed in order by 
ataxia, relaxation of the wings, and a stretching 
of the legs (Fig. 2), which were relaxed only 
terminally. Hypersalivation and difficulty in 
swallowing were apparent. Respiratory arrest 
preceded a final convulsive effort before com- 
plete cessation of movement. 
Rats and guinea pigs show symptoms quite 
similar to those of the mouse. Kittens, on the 
other hand, passed through a short but violent 
wretching and vomiting stage. Hyperventila- 
tion, relaxation of the vocal cords and nic- 
titating membrane, and dilation of the pupils 
followed. Relaxation of forepaws and neck 
muscles preceded respiratory distress, violent 
tail wagging, terminal respiratory arrest, and 
relaxation of the bladder sphincter muscles. 
DISCUSSION AND CONCLUSIONS 
The common denominator of the lethal symp- 
toms observed seems to be respiratory paralysis 
with no other noticeable lethal effects. Frogs, 
though able to survive doses paralyzing their 
lung respiration for 15 hr. or more, succumbed 
sporadically to a wide range of much larger 
doses. This may indicate other less dominant 
