146 ESSENTIALS OF VETERINARY LAW 



horse, and each slide should be so marked as to 

 be proper evidence to present in trial of possible 

 future action in the case. In such cases the court 

 would not be reviewing the diagnosis, but it might 

 set the diagnosis aside as a violation of discretion, 

 in that the veterinarian had not made use of ap- 

 proved methods of diagnosis."" 



109. Jurisdiction in Quarantine. Questions as 

 to jurisdiction in quarantine occasionally arise.'* 

 First it must be remembered that the authority of 

 Congress, and consequently of federal officers and 

 employees, is found in the power to regulate inter- 

 state and foreign commerce. ' ' Disease, pestilence, 

 and pauperism are not subjects of commerce, al- 

 though among its attendant evils. They are not 

 things to be regulated and trafficked in, but to 

 be prevented, as far as human foresight or human 

 means can guard against them. ' ' ^^ Therefore 

 ' * Congress has not only the right to pass laws reg- 

 ulating legitimate commerce among the states and 

 with foreign nations, but also it has full power to 

 bar from the channels of such commerce illicit and 

 harmful articles. ' ' ^^ The federal government thus 

 has power under the commerce clause to main- 

 tain such inspection and quarantine as may be 

 necessary to prevent the introduction of infectious 

 diseases or their germs from foreign countries, 

 or into one state from another. Ordinarily the 

 individual states may do nothing which would 

 interfere with the federal control over interstate 



83 Public Health, 407. Peirce v. New Hampshire, 5 



34 Public Health, 408. How. 504. 



35 License Cases, Thurlow v. 36 McDermott v. Wisconsin, 

 Mass ; Fletcher v. Ehode Island ; 228 U. S. 115. 



