188 ESSENTIALS OF VETERINARY LAW 
from infectious disease, or quarantined under the 
supervision of an inspector of the bureau; but 
horses driven or ridden in for a period of not more 
than three days, or when returning after an ab- 
sence in Canada of not more than three days, are 
not subject to such restrictions. Horses belonging 
to Indian tribes, settlers and immigrants, or in 
connection with stock raising or mining, and those 
intended for temporary stay not to exceed two 
weeks, may be admitted without inspection upon 
written permission of the Secretary of Agricul- 
ture; otherwise they must be inspected at point of 
entry. 
The importation of tick infested horses from 
Mexico is generally prohibited until after satis- 
factory treatment. All ruminants, swine or horses 
imported from Mexico must be free from infectious 
disease, but tick infested cattle may be shipped for 
immediate slaughter to points in Texas. Unless 
accompanied by satisfactory evidence of freedom 
from exposure to infectious disease the animals 
will be quarantined. 
142. Federal Supervision at Slaughterhouses. 
The federal control over interstate and foreign 
transportation of animals is exclusive, and inci- 
dentally this practically includes intrastate move- 
ments as well. In supervision of the slaughtering 
industry the federal supervision is distinct from 
that which should be used over the intrastate in- 
dustry. Here also the supervision is under the 
eare of the Bureau of Animal Industry; but in 
many states the local business is practically free 
from supervision, and animals condemned by 
bureau inspectors may sometimes, and those which 
