512 HAsSTINGS—POLICE POWER OF THE STATE, [June 19, 
Justice Marshall, that it is a constitution which is to be interpreted. 
In the other case of individual rights the language of the constitu- 
tion is expressly held to have been adopted, in view of the inter- 
pretation of those rights by the common law and their real extent 
to be determined by legal precedents. 
In applying the commerce clause, too, the fear of mutually hos- 
tile action on the part of the states, which has been before men- 
tioned as the real motive for the adoption of the constitution, not 
only fixed the color of all the early precedents on this subject and 
established a tradition, but has actively operated ever since, and 
with good reason as many state enactments show. 
The interstate commerce clause of the federal constitution was 
however vainly invoked in the case of *Smith vs. Alabama. The 
Supreme Court of that state had affirmed a judgment dismissing 
habeas corpus proceedings brought by Smith, a locomotive engineer, 
who had been arrested for driving a locomotive on a regular pas- 
senger train of the Mobile & Ohio Railway Company from 
Mobile, Ala., to Corinth, Miss., being sixty miles in Alabama and 
two hundred and sixty-five miles in Mississippi. At Corinth he 
took charge of a through train from St. Louis and brought it back 
to Mobile, drawing both ways express and mail matter and passen- 
gers destined for different states. 
He had been committed to jail for violation of the provisions of 
an Alabama law requiring an examination and a license to author- 
ize an engineer to engage in such an employment. It was admitted 
that he had not taken the examination nor procured a license for 
driving a locomotive, and that the law provided a penalty of not 
less than fifty nor more than five hundred dollars for engaging in 
such employment in that state without the license. The law was 
claimed to be void as being a regulation of commerce and so an 
infringement on the exclusive power of Congress. 
The court in an opinion by Justice Matthews finds the law valid 
and that the state had such power over persons in its jurisdiction 
whose business was interstate commerce : 
“There are many cases where the acknowledged powers in the state 
may be exerted and applied in such a manner as to affect foreign or 
interstate commerce without being intended to operate as commercial 
regulations. If their operation and application in such cases regulate 
such commerce so as to conflict with the regulation of the same subject 
1 124 U. S., 465 (1888). 
