4 BULLETIN 1274, U. S. DEPARTMENT OF AGRICULTURE 
Kinsley, 1909, tells of a case in which one hundred 6-months-old 
shotes were turned into a 40-acre field on which cocklebur was just 
coining up through the ground. The hogs were seen to eat the. 
young plants and seven of them died. He gives the details of a post- 
mortem examination. 
Pommel, in his Manual of Poisonous Plants, 1910 and 1911, while 
quoting statements of the poisonous properties of Xanthium, says: 
" The injury from this plant probably comes largely from its me- 
chanical action," and he quotes others in substantiating this belief. 
In articles by Pammel in the American Journal of Veterinary 
Medicine, of 1918, 1919, 1920, and 1921, quoting statements of the 
poisonous properties of the plant, he gives the impression that he 
still thinks the chief injuries by cocklebur are mechanical. 
In Cooperative Manager and Farmer, 1917, the following state- 
ment is made which apparently is based on work by the Missouri 
Experiment Station : " Cockleburs in pastures are particularly dan- 
gerous for pigs and shotes. The burs get inside the stomach of the 
animal and inflame the lining, causing death, which is the usual 
result. Even the plants themselves are poisonous to hogs, but most 
authorities think it is the old, matured bur that does the most 
damage." 
Maiden, 1918, states that a dermatitis is produced in those who 
handle XaMhiwm strumarium. He made a similar statement in 
1921. 
In Bulletin 185 of the Alabama Experiment Station, 1920, occurs 
the following statement by Cary : " Young cockleburs are said to be 
poisonous to pigs, but our feeding tests disprove it. YVe could not 
kill pigs by feeding them young cockleburs. Jimson weeds grow 
with cockleburs, and Jimson weeds are very poisonous." 
Hansen, 1920, makes the following statement: "Although fatal 
results are generally attributed to poisoning, there is little evidence 
to substantiate this theory. The harmful effects are largely due to 
the mechanical action of the spiny burs, which are injurious in sev- 
eral ways. These burs may (1) irritate the walls of the stomach, 
causing inflammation and sometimes death; (2) lodge in the throat 
and thus choke the animal; or (3) clog the intestinal tract, fre- 
quently with fatal results. Overeating the young and succulent 
plants may cause bloating, which is similar in nature to bloating 
caused by succulent clover, corn, etc. The hairy leaves are also said 
to cause severe itching." 
Johnson and Archer, 1922, make the following statement : " The 
injury from this plant most likely occurs from mechanical obstruc- 
tion rather than from poison. The plant has been reported to 
contain a poisonous glucoside, although Doctor Bitting was unable 
to obtain any poisonous properties in the growing plant. Cases 
investigated by the senior writer on post-mortem proved that the 
thorny bristles were a factor in causing mechanical obstruction and 
extreme irritation to the mucous surface of the intestine.'' 
Kinsley, 1922, gives a general description of cocklebur poisoning 
in swine with symptoms and lesions. This is an excellent resume 
of the subject but apparently is not based on any definite experi- 
mental evidence. 
