Arsenic Toxicity Studies— Clements and Munson 
153 
applied to orchards and fields. As Headden and 
Swingle had warned, the continued application 
and the resulting accumulations of arsenic in the 
surface layers of soil and its retention there re¬ 
sulted in crop reduction or failure in Washington 
as reported by Vandecaveye, Horner, and Keaton 
(1936), in South Carolina as reported by Albert 
and Paden (1931) and Cooper et al. (1931), and 
in Louisiana as reported by Reed and Sturgis 
(1936). During the past 15 years, experimental 
work on arsenic has been directed to several prob¬ 
lems: the contamination of plant parts which are 
used as animal or human food, the levels at which 
arsenic in soil may cause a reduction in crop yields, 
and methods which might be used to render a 
poisonous soil suitable for renewed crop produc¬ 
tion. 
Recent work: Arsenic in food .—Chorley and Mc- 
Chlery (1935), interested in the poisoning of fowls 
following their consumption of poisoned locusts, 
reported that when arsenic is administered in 
small quantities such as occur on sprayed grass¬ 
hoppers, a domestic fowl can tolerate compara¬ 
tively large doses over a long period without any 
visible ill effects. 
Franke and Maxon (1936) gave rats intraperi- 
toneal injections of disodium acid arsenite and 
disodium acid arsenate, as well as other chemicals. 
The minimum fatal doses were defined as the 
smallest doses which would kill 75 per cent or 
more of the animals in less than 2 days. The mini¬ 
mum fatal doses of the arsenite were 4.25-4.75 
mg. of arsenic per kilogram of weight, whereas for 
the arsenate, the fatal dose was 14-18 mg. per 
kilogram. 
Groves, McCulloch, and St. John (1946) con¬ 
cluded from their studies that lead arsenate spray 
residues are much less toxic to swine than has gen¬ 
erally been supposed. One pig consumed the spray 
residue from 1,007 kilograms (over 1 ton) of 
heavily sprayed apples which contained 114.8 gm. 
of lead arsenate in the form of spray residue. The 
pig gained in weight approximately as much as 
the control pig, and no abnormalities were appar¬ 
ent in blood studies on it. Data showed that of 
the edible portions of the pigs which were fed 
large quantities of lead arsenate, only the livers 
contained more lead than the 7.14 ppm legal limit, 
and none of the organs analyzed contained more 
than the limit of 3.57 ppm of As 2 0 3 . 
The effect which spray residues on plant parts 
and metabolized arsenic contained within plant 
tissue may have on higher animals, including 
humans, has been receiving increasing attention. 
Talbert and Tayloe (1933), reporting results of 
feeding spray chemicals to rats, concluded that if 
it may be assumed that the spray chemicals have 
an effect upon man similar to that which they 
have on albino rats, it is their opinion that there 
is little likelihood that a human being would con¬ 
sume as spray residue on apples, sprayed and 
handled in the usual manner, enough arsenic 
either at one time or over an extended period to 
be injurious. 
Coulson, Remington, and Lynch (1934) com¬ 
pared the bodies of rats fed for 3 to 5 V 2 months 
on diets of varying arsenic content derived (1) 
from natural shrimp and (2) from added arsenic 
trioxide. The bodies of animals which had re¬ 
ceived the largest amount of arsenic, 17.9 mg. per 
kilogram, in the form of shrimp contained at least 
four times as much arsenic as the stock diet con¬ 
trols, whereas those which received approximately 
the same quantity of arsenic in the form of arsenic 
trioxide contained 55 to 65 times as much as the 
controls. An even greater difference between the 
storage of arsenic from the two forms was shown 
during the first 3 months than after 5 V 2 months, 
a fact suggesting that the rats receiving the inor¬ 
ganic arsenic had at some period during the first 
3 months reached an equilibrium, after which no 
further storage took place. 
There was no retardation of growth in any of 
the arsenic fed animals nor any observable differ¬ 
ences in their physical vigor or appearance, and 
in none of them was there any histological evi¬ 
dence of injury to the spleen, liver, or kidney due 
to the feeding of arsenic at the level employed. 
These authors (1935) further emphasized the 
difference between metabolized and inorganic ar¬ 
senic in foods by showing that arsenic as present 
in shrimp was found to be far less available for 
storage in young rats than when fed at the same 
level as As 2 0 3 . During the first 3 months of their 
feeding trial, 18 per cent of the As 2 0 3 incorporated 
in the diet at a level of 17.9 mg. per kg. was stored 
as against 0.77 per cent for the same amount of 
arsenic in shrimp. The total amount stored was 
not significantly increased by feeding the element 
for an added 9 months. There was no evidence of 
toxicity from the arsenic in either form after 12 
months of feeding. 
In two human subjects studied by these authors, 
the ingestion of shrimp in amounts furnishing 
1,180 and 980 gammas of arsenic was followed 
by rapid and complete elimination of the arsenic. 
Inorganic arsenic, although excreted more slowly 
than shrimp arsenic, was apparently eliminated 
more completely by these subjects than by the rats. 
These results are considered to be of interest not 
only for the light which they throw on the meta¬ 
bolism of arsenic, but also as additional evidence 
that the manner in which inorganic elements are 
used in the body depends upon the source or form 
in which these elements are presented. 
It appears, therefore, that arsenic which has 
been metabolized by an organism—that is, arsenic 
which the organism has absorbed and made a part 
of itself—is less dangerous to animals than is in¬ 
organic arsenic such as may appear on the leaves 
of plants shortly after spraying. This latter arsenic 
is quite poisonous to livestock, as most sections of 
