COCKLEBURS AS POISONOUS PLANTS 17 
In Table 3 the time was computed from the first to the last- 
noted symptom. It is; evident that in many cases this does not show 
the actual duration of illness. Inasmuch as the animals were not 
under constant observation, they were in some cases undoubtedly 
sick before the first symptom was noted, and doubtless in many 
cases the illness continued after the last-noted symptom. In some 
the first symptom was noted in the morning after a. night during 
which no observations were taken. This accounts for the very 
short time of cattle 945 because when the first symptom was noted 
in the morning the animal was already very sick. Table 3, however, 
gives in a, general way a fair indication of the time during which 
the animals were sick. Excluding cattle 945, the shortest period of 
illness was in the case of pig 26 which was sick 1 hour and 35 
minutes and recovered. The longest period which any animal 
was sick was in the case of chicken 37, which recovered after an 
illness of 24 hours. 
If the time of symptoms recorded is compared with the dosage 
which the animals received it will be seen that there is no clear 
correlation between them. 
EFFECT OF CONTINUED FEEDING 
Three pigs were fed Xanthium daily for a considerable period. 
Pig 12 was fed from June 13 to' July 9, with the exception of four 
days, receiving daily doses varying from 0.313 to 2.856 per cent of 
its weight. On June 23 it received 2.125 per cent, June 24, 1.966, 
June 25, 1.574, and June 26, 1.574. On June 28 and June 29, and 
on July 4, 5, and 6, it received daily 1.574 per cent of its weight. 
Pig 10, from July 13 to 20, with the exception of one day, received 
the plant daily in doses varying from 0.378 per cent of its weight 
to 1.749 per cent. On July 17 it received 1.512 per cent of its weight 
and on July 18, 1.749 per cent, with no- effect. 
Pig 32 from August 25 to August 26 received daily doses of 
1.102 per cent of its weight, and on September 5, 6, 8, 10, and 11 
received 1.333 per cent. 
It has been found, as shown on page 15, that the minimum 
toxic dose of the plant, in the young cotyledon stage, is 0.736 per cent 
of the pig's weight, and the minimum lethal dose is 1.496 per cent. 
These animals then, in some cases, received on successive days not 
only more than the toxic dose but more than the lethal dose. With 
the exception of pig 12, which received on the first day 2.856 per 
cent of its weight, all the animals received in the first feedings less 
than the toxic dose. All these feedings were of the plant in the 
young cotyledon stage. After it was found that the plant was 
most poisonous before the growth of the leaves, great care was 
used to collect for the routine feeding only the very young plants. 
Less attention was paid to this in the early part of the work; while 
the notes are incomplete in regard to the collections used, it is 
known that some of the material used for pigs 10 and 12 was in the 
2 and 4 leaf stages. This probably explains the failure to poison 
pig 12 on 2.856 per cent of its weight. Making some allowance for 
the indefiniteness in regard to the age of the plant in some of the 
feedings, it is still noticeable that pigs 10 and 12 on successive days 
could receive such large quantities with no resulting symptoms. 
