SECTION III 
Plants Dangerous in Ground Feeds 
Many plants have poisonous seeds. Indeed in many 
species there is a tendency for the poison to be collected 
from other parts of the plant and concentrated in the 
seed. These poisonous seeds are of great importance in 
Canada, where they form a considerable proportion of 
the screenings, millions of bushels of which are cleaned 
from grain annually. It has been customary for millers 
to mix the screenings from the wheat they grind, with 
their bran and shorts. In the early days the screenings 
obtained at the large grain elevators of the west were 
destroyed, but of late years they also have been used in 
the manufacture of feeds. This practice, which has been 
fairly successful in the United States, has caused much 
trouble in Canada, where the screenings on the average 
contain a much larger proportion of poisonous seeds. The 
loss from this source has been confined, for the most part, 
to swine. Complaints have, however, come from men in 
other branches of the livestock business, especially those 
engaged in dairying, who claim that a great deal of 
sporadic abortion has been caused by the use of feed con- 
taining screenings. 
Much investigation into the character of our native 
weed seeds is still needed, and it is probable that species 
not now known to be harmful will be definitely proved so 
in the future. This section gives a resumé of the facts 
so far ascertained. 
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