GOVERNMENTAL SERVICES 147 
traffic, and the authority of the nation begins with 
the shipment of the goods, and only ends when the 
goods are sold, or mixed with the property of the 
state.*7 A shipment from one point in a state to 
another point in the same state, but where the 
goods pass through a point in another state, is 
interstate commerce.*® ‘‘Although, from the na- 
ture and subject of the power to regulate com- 
merce, it must be exercised by the national gov- 
ernment exclusively, this has not been held to be 
so where in relation to the subject matter different 
rules might be suitable in different localities. At 
the same time, Congress could by affirmative act 
displace the local laws, and substitute laws of its 
own, and thus correct any unjustifiable and op- 
pressive exercise of power by state legislation.’’ 3° 
While, therefore, even in such cases Congress still 
has power to act, in matters pertaining to localized 
conditions and dangers Congress has elected to 
let the several states regulate the matter of pro- 
tecting the public health as to themselves seemed 
best.*° Because disease is not a fit subject of com- 
merce, state officers have maintained quarantine 
at their borders, although the subjects of the 
quarantine had already been passed by federal 
officers of health, and the federal courts have 
denied their own right to interfere by an injunc- 
tion; and the costs and charges of such quarantine 
inspection under state laws may be lawfully im- 
37 Brown v. Maryland, 12 Fear & Y. V. R. RB, 298. C. 
Wheat. 419. 510. 
38 Hanley v. Kansas City 8. 39 Louisiana v. Texas, 176 U. 
Ry. Co., 187 U. 8. 617; Statev. S. 1. 
St. P., M. & O. Railroad Co., 40 40 Bartlett v. Lockwood, 160 
Minn, 267; Sternberger v. Cape U.S. 357. 
