Rhodactis — E. J. MARTIN 
405 
DOSE IN fJLl/g 
FIG. 1. Relation of dose to survival time of Bufo 
marinus injected with "fresh” Rhodactis howesii. At 
each dose level, two dots show the highest and lowest 
mean obtained in 15 assays. In each assay, five toads 
were used at each dose level. 
reaction. (3) Sea anemones were mixed with 
3 times their volume of ethyl alcohol and kept 
at 25-30° C. for 14 days, after which the mix- 
ture was dialyzed and assayed. It was found that 
mean survival times at doses of 4 and 8 /zl/g 
were the same as in the controls, but at doses 
of 1 and 2 /xl/g they were significantly prolonged. 
(4) Sea anemones, without addition of any sub- 
stance, were kept at 3° C. for 14 days, after 
which they were assayed. The dose effect curves 
were found to be the same as in the controls. 
Among the preserving procedures tested, 
refrigeration proved to be the only one suit- 
able for our purpose. 
DISCUSSION 
The following discussion is based on the 
assumption that the poison which caused death 
of the toads is the same as that which caused 
death of the humans. Its nature is unknown. 
According to one classification, "marine poi- 
sons” may be of infectious, allergic, or paralytic 
type (Muller, 1935). Neither the symptoms of 
our patients nor prevailing environmental con- 
ditions suggested banal infectious agents as the 
cause of the poisonings. Furthermore, persons 
who repeatedly manipulated both the sea anem- 
one on the reefs and its homogenates in the 
laboratory with their bare fingers did not ex- 
perience the sensation of being stung nor did 
they manifest any skin lesions at later dates. 
Thus it is uncertain whether the discharge of 
the nematocysts of R. howesii is capable of in- 
juring the human tegument and whether the 
poison is contained in the nematocysts or in the 
tissues (Phillips, 1956). But it is certain that 
for human skin the allergenic potentialities of 
R. howesii are negligible as compared with those 
of some other sea anemones and of squids ( Son- 
derhoff, 1936; Halstead, 1957). 
The poison of R. hotvesii seems to be of the 
paralytic type and, as is the case with the 
paralytic poisons of mussels and clams, it can 
be assumed that it is composed of more than 
one toxic principle ( Sommer and Meyer, 1937 ) . 
However, it differs from these in several 
respects. In poisonings with R. howesii the 
stage of stupor is long and cannot escape any 
observer, while mussel and clam poisonings seem 
more rapidly fatal, and a stage of stupor — if it 
exists — seems not to be impressive (Meyer, 
1928; Medcof et al. , 1947; Tennant et al., 1955 ) . 
The degree of toxicity of mussels and clams 
changes with the seasonal variations of the 
density of poisonous dinoflagellates in the plank- 
ton (Sommer et al., 1937), but R. howesii 
showed no seasonal change in toxicity. 
Some toxic marine invertebrates have been 
found to derive their poison from one or the 
other of the following: their own tissue metab- 
olism (Erspamer and Benati, 1953), the metab- 
olism of a symbiont which lives in the tissue of 
the invertebrate (Zahl and McLaughlin, 1957), 
and the ingestion of poisonous plankton (Mc- 
Farren et al., 1957 ) . By analogy it can be spec- 
ulated that one or the other of these modalities 
may apply to R. howesii. 
Various sea anemones have been found to 
contain homologues of amines and ammonium 
bases of varying degrees of toxicity ( Ackermann 
et al., 1923; Ackermann and Janka, 1953; Welsh, 
1955) and high proportions of fatty acids and 
