GOVERNMENTAL SERVICES 147 



traffic, and the authority of the nation begins with 

 the shipment of the goods, and onl}^ ends when the 

 goods are sold, or mixed with the property of the 

 state. ^' 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. ' ' ^^ 

 "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. E. E., 29 S. C. 

 Wheat. 419. 510. 



38 Hanley v. Kansas City S. 39 Louisiana v. Texas, 176 U. 

 Ey. Co., 187 U. S. 617; State v. S. 1. 



St. P., M. & O. Eailroad Co., 40 4o Bartlett v. Lockwood, 160 



Minn. 267 ; Sternberger v. Cape U. S. 357. 



