2 BULLETIN 1274, U. S. DEPARTMENT OF AGRPCULIURE 
essential facts, and. while much more work can be done, the impor- 
tance of the subject makes it seem wise to issue a publication which 
will discuss the subject in a definite manner. 
HISTORICAL SUMMARY 
In the discussion of cockleburs (species of Xanthium) as stock- 
poisoning plants, no attempt has been made to distinguish the dif- 
ferent species. The species are closely allied and, there is reason to 
think, do not differ materially in their poisonous properties. Many 
of the articles which have been written on cockleburs were not writ- 
ten by technical botanists, neither were the plants submitted to 
botanists for determination, so that it is probable that the species in 
many cases were incorrectly named. 
The history of the species of Xanthium as stock-poisoning plants 
is comparatively modern. The first statement that was found in re- 
gard to the injurious effect of these plants upon domestic animals 
was made by Doctor Bancroft in 1880 in a paper read before the 
Queensland (Australia) Physiological Society. It has been impos- 
sible for the writers to see the original paper, but the information in 
regard to it was obtained from a review by Heldreich in the 
Botanische Centralblatt. 1880. It is stated that, on the estate of a 
Mr. Yates, a large number of cows, one horse, and a sheep had been 
killed by eating the young plants of Xanthium strumwrium. The 
animals fell upon the ground and died very quickly. Doctor Ban- 
croft made an extract of the plant, with which he poisoned small 
animals and obtained the same results with extracts of the species 
Xanthium spinosvm. The reviewer calls attention to the fact that 
although two species of Xanthium are widely distributed in central 
and southern Europe there are no reports there of cases of poison- 
ing. The cocklebur in Queensland, of course, was an introduced 
plant. 
Zander, 1881, quotes a letter from Heimberger to the effect that 
cases of poisoning have arisen from the seeds and oil of Xanthium 
strumarium. He states that the oil has been pressed out for com- 
mercial purposes. All who have eaten the oil or the seeds were made 
exceedingly sick and several children died. On this account an in- 
vestigation had been made but no poisonous substance had been 
found. He reported that he had made experiments on cats and dogs 
vith the oil with no results, although one of the workers was made 
sick after taking about 10 of the seeds. Zander himself made some 
experiments with cats and frogs with no tangible results. 
Cheatham. 1884. states that cocklebur is one of the first plants that 
appear in the spring, and that in some of the Southern and Western 
States the swine which run at large are very fond of the young 
plants and almost invariably die after eating them, and that antidotes 
had not been used with any success. He explained some chemical 
work which was done on the plant. 
< ioff. 1804. makes the following statement : " It has been said that 
the plant is poisonous to cattle, but this is probably a mistake. It is 
nt leasl known that cattle sometimes eat sparingly of it without 
