itself, the greatest of all rights, is not unrestricted license to act according to one's own will. It is only freedom from restraint under conditions essential to the equal enjoyment of the same right by others. It is then liberty regulated by law." In the constitution of Massachusetts adopted in 1780 it was laid down as a fundamental principle of the social compact that the whole people covenants with each citizen, and each citizen with the whole people, that all shall be governed by certain laws for "the common good," and that government is instituted "for the common good, for the protection, safety, prosperity and happiness of the people, and not for the profit, honor or private interests of any one man, family or class of men." The good and welfare of the Commonwealth, of which the legislature is primarily the judge, is the basis on which the police power rests in Massachusetts. Commonwealth v. Alger, 7 Cush. 53, 84.

Applying these principles to the present case, it is to be observed that the legislature of Massachusetts required the inhabitants of a city or town to be vaccinated only when, in the opinion of the Board of Health, that was necessary for the public health or the public safety. The authority to determine for all what ought to be done in such an emergency must have been lodged somewhere or in some body; and surely it was appropriate for the legislature to refer that question, in the first instance, to a Board of Health, composed of persons residing in the locality affected and appointed, presumably, because of their fitness to determine such questions. To invest such a body with authority over such matters was not an unusual nor an unreasonable or arbitrary requirement. Upon the principle of self-defense, of paramount necessity, a community has the right to protect itself against an epidemic of disease which threatens the safety of its members. It is to be observed that when the regulation in question was adopted, smallpox, according to the recitals in the regulation adopted by the Board of Health, was prevalent to some extent in the city of Cambridge and the disease was increasing. If such was

the situation—and nothing is asserted or appears in the record to the contrary-if we are to attach any value whatever to the knowledge which, it is safe to affirm, is common to all civilized peoples touching smallpox and the methods most usually employed to eradicate that disease, it cannot be adjudged that the present regulation of the Board of Health was not necessary in order to protect the public health and secure the public safety. Smallpox being prevalent and increasing at Cambridge, the court would usurp the functions of another branch of government if it adjudged, as matter of law, that the mode adopted under the sanction of the State, to protect the people at large, was arbitrary and not justified by the necessities of the case. We say necessities of the case, because it might be that an acknowledged power of a local community to protect itself against an epidemic threatening the safety of all, might be exercised in particular circumstances and in reference to particular persons in such an arbitrary, unreasonable manner, or might go so far beyond what was reasonably required for the safety of the public, as to authorize or compel the courts to interfere for the protection of such persons. Wisconsin &c. R. R. Co. v. Jacobson, 179 U. S. 287, 301; 1 Dillon Mun. Corp., 4th ed., §§ 319 to 325, and authorities in notes; Freund's Police Power, § 63 et seq. In Railroad Company v. Husen, 95 U. S. 465, 471-473, this court recognized the right of a State to pass sanitary laws, laws for the protection of life, liberty, health or property within its limits, laws to prevent persons and animals suffering under contagious or infectious diseases, or convicts, from coming within its borders. But as the laws there involved went beyond the necessity of the case and under the guise of exerting a police power invaded the domain of Federal authority and violated rights secured by the Constitution, this court deemed it to be its duty to hold such laws invalid. If the mode adopted by the Commonwealth of Massachusetts for the protection of its local communities against smallpox proved to be distressing, inconvenient or objectionable to some-if nothing more could be reasonably

affirmed of the statute in question-the answer is that it was the duty of the constituted authorities primarily to keep in view the welfare, comfort and safety of the many, and not permit the interests of the many to be subordinated to the wishes or convenience of the few. There is, of course, a sphere within which the individual may assert the supremacy of his own will and rightfully dispute the authority of any human government, especially of any free government existing under a written constitution, to interfere with the exercise of that J will. But it is equally true that in every well-ordered society charged with the duty of conserving the safety of its members the rights of the individual in respect of his liberty may at times, under the pressure of great dangers, be subjected to such restraint, to be enforced by reasonable regulations, as the safety of the general public may demand. An American citizen, arriving at an American port on a vessel in which, during the voyage, there had been cases of yellow fever or Asiatic cholera, although apparently free from disease himself, may yet, in some circumstances, be held in quarantine against his will on board of such vessel or in a quarantine station, until it be ascertained by inspection, conducted with due diligence, that the danger of the spread of the disease among the community at large has disappeared. The liberty secured by the Fourteenth Amendment, this court has said, consists, in part, in the right of a person "to live and work where he will," Allgeyer v. Louisiana, 165 U. S. 578; and yet he may be compelled, by force if need be, against his will and without regard to his personal wishes or his pecuniary interests, or even his religious or political convictions, to take his place in the ranks of the army of his country and risk the chance of being shot down in its defense. It is not, therefore, true that the power of the public to guard itself against imminent danger depends in every case involving the control of one's body upon his willingness to submit to reasonable regulations established by the constituted authorities, under the

sanction of the State, for the purpose of protecting the public collectively against such danger.

It is said, however, that the statute, as interpreted by the state court, although making an exception in favor of children certified by a registered physician to be unfit subjects for vaccination, makes no exception in the case of adults in like condition. But this cannot be deemed a denial of the equal protection of the laws to adults; for the statute is applicable equally to all in like condition and there are obviously reasons why regulations may be appropriate for adults which could not be safely applied to persons of tender years.

Looking at the propositions embodied in the defendant's rejected offers of proof it is clear that they are more formidable by their number than by their inherent value. Those offers in the main seem to have had no purpose except to state the general theory of those of the medical profession who attach little or no value to vaccination as a means of preventing the spread of smallpox or who think that vaccination causes other diseases of the body. What everybody knows the court must know, and therefore the state court judicially knew, as this court knows, that an opposite theory accords with the common belief and is maintained by high medical authority. We must assume that when the statute in question was passed, the legislature of Massachusetts was not unaware of these opposing theories, and was compelled, of necessity, to choose between them. It was not compelled to commit a matter involving the public health and safety to the final decision of a court or jury. It is no part of the function of a court or a jury to determine which one of two modes was likely to be the most effective for the protection of the public against disease. That was for the legislative department to determine in the light of all the information it had or could obtain. It could not properly abdicate its function to guard the public. health and safety. The state legislature proceeded upon the theory which recognized vaccination as at least an effective if not the best known way in which to meet and suppress the

evils of a smallpox epidemic that imperilled an entire population. Upon what sound principles as to the relations existing between the different departments of government can the court review this action of the legislature? If there is any such power in the judiciary to review legislative action in respect of a matter affecting the general welfare, it can only be when that which the legislature has done comes within the rule that if a statute purporting to have been enacted to protect the public health, the public morals or the public safety, has no real or substantial relation to those objects, or is, beyond all question, a plain, palpable invasion of rights secured by the fundamental law, it is the duty of the courts to so adjudge, and thereby give effect to the Constitution." Mugler v. Kansas, 123 U. S. 623, 661; Minnesota v. Barber, 136 U. S. 313, 320; Atkin v. Kansas, 191 U. S. 207, 223.

Whatever may be thought of the expediency of this statute, it cannot be affirmed to.be, beyond question, in palpable conflict with the Constitution. Nor, in view of the methods employed to stamp out the disease of smallpox, can anyone confidently assert that the means prescribed by the State to that end has no real or substantial relation to the protection of the public health and the public safety. Such an assertion would not be consistent with the experience of this and other countries whose authorities have dealt with the disease of smallpox.1 And the principle of vaccination as a means to

1 "State-supported facilities for vaccination began in England in 1808 with the National Vaccine Establishment. In 1840 vaccination fees were made payable out of the rates. The first compulsory act was passed in 1853, the guardians of the poor being entrusted with the carrying out of the law; in 1854 the public vaccinations under one year of age were 408,825 as against an average of 180,960 for several years before. In 1867 a new Act was passed, rather to remove some technical difficulties than to enlarge the scope of the former Act; and in 1871 the Act was passed which compelled the boards of guardians to appoint vaccination officers. The guardians also appoint a public vaccinator, who must be duly qualified to practice medicine, and whose duty it is to vaccinate (for a fee of one shilling and sixpence) any child resident within his district brought to him for that purpose, to examine the same a week after, to give a certificate, and to certify to the vaccination officer the fact of vaccination or of insusceptibility.