When there are reasonable economic or political or social reasons for doing so, certain ocupations or industries, or even classes of persons may be selected out for special regulation or for the enjoyment of special privileges.

Thus, for example, the practice of certain professions may be limited to persons of the male sex, or to those of a certain age, or to those possessing other qualifications that may reasonably be held to indicate a fitness for the profession.22

Thus also, as proper police measures, the States are permitted to impose special restrictions and liabilities upon railway corporations. Special modifications of the common-law doctrine of employer's liability with reference to them have been upheld, as have laws placing the presumption of negligence upon them when cattle have been killed by their trains, and laws making them responsible for fires kindled by sparks from their locomotives, though they may have taken every possible precaution to avoid such fires.23

However, in Gulf, etc., Ry. Co. v. Ellis24 a state law was held void which imposed an attorney's fee in addition to costs upon railway companies which should fail to pay certain claims within a certain time after presentation. Here the court held that there was no reasonable relation between the burden imposed and the peculiar character of the business done.25

Neal v. Delaware, 103 U. S. 370; 26 L. ed. 567; and Soon Hing v. Crowley, 113 U. S. 703; 5 Sup. Ct. Rep. 730; 28 L. ed. 1143. See also Grunding v. Chicago, 177 U. S. 183; 20 Sup. Ct. Rep. 633; 44 L. ed. 725. But see as to doctrine declared in Wilson v. Eureka City, 173 U. S. 32; 19 Sup. Ct. Rep. 317; 43 L. ed. 603.

21 Chapter XXXVIII (Election Of Members Of Congress. 234. Their Apportionment Among The States).

22 Re Lockwood, 154 U. S. 116; 14 Sup. Ct. Rep. 1082; 38 L. ed. 929; Brad-well v. Illinois, 16 Wall. 130; 21 L. ed. 442.

23 See especially St. Louis, etc., Co. v. Mathews, 165 U. S. 1; 17 Sup. Ct. Rep. 243; 41 L. ed. 611; Missouri Pacific Ry. Co. v. Mackey, 127 U. S. 205; 8 Sup. Ct. Rep. 1161; 32 L. ed. 107.

24 165 U. S. 150; 17 Sup. Ct. Rep. 255; 41 L. ed. 666.