as repeatedly acquiesced in the enforcement of State laws.
* * * Such laws undoubtedly operate upon interstate and foreign
commerce. They could not be effective otherwise. They cannot, of course,
be made the cover for discriminations and arbitrary enactments having no
reasonable relation to health * * *; but the power of the State to take
steps to prevent the introduction or spread of disease, although
interstate and foreign commerce are involved (subject to the paramount
authority of Congress if it decides to assume control), is beyond
question.[899] * * * State inspection laws and statutes designed to
safeguard the inhabitants of a State from fraud and imposition are valid
when reasonable in their requirements and not in conflict with Federal
rules, although they may affect interstate commerce in their relation to
articles prepared for export or by including incidentally those brought
into the State and held for sale in the original imported
packages."[900]

QUARANTINE LAWS

In two earlier cases a Missouri statute which prohibited the driving of
all Texan, Mexican, and Indian cattle into the state during certain
seasons of the year was held void;[901] while a statute making anybody
in the State who had Texas cattle which had not wintered north of a
certain line liable for damage through the communication of disease from
these to other cattle was sustained;[902] as were also the regulations
of a sanitary commission which excluded all cattle, horses, and mules,
from the State at a certain period when anthrax was prevalent.[903]
Reviewing previous cases in the one last cited, the Court declared their
controlling principle to be simply whether the police power of the State
had been exerted to exclude "_beyond what is necessary for any proper
quarantine_," a question predominantly of fact, and one therefore to be
determined for each case with only general guidance from earlier
decisions.[904]

More recent cases conform to the same pattern. Among measures sustained
are the following: an Ohio statute forbidding the sale in that State of
condensed milk unless made from unadulterated milk;[905] a New York
statute penalizing the sale with intent to defraud of preparations
falsely represented to be Kosher;[906] a New York statute requiring that
cattle shall not be imported for dairy or breeding purposes unless
accompanied by the certificate of a proper sanitary official in the
State of origin, in order to prevent the spread