The action is for alleged false imprisonment. The alleged defense is that in what the defendant did in the premises he was *11acting as commissioner of health of the city of Brooklyn pursuant to authority conferred by statute, which provides that “ In the presence of great and imminent peril to public health of the. city of Brooklyn by reason of impending pestilence, it shall be the duty of said commissioner to take such measures and do and order, and cause to be done, such acts, and make such expenditures * * * for the preservation of the public health from such impending pestilence as he may, in good faith, declare the public safety and health to demand, and the mayor of said city and the president of the medical society of Kings county, shall also in writing approve.” (Laws of 1888, chap. 583, tit. 12, § 5.)
The general statute relating to “ Local Boards of Health ” also provides that “ Every such local board of health shall guard against the introduction of contagious and infectious diseases by the exercise of proper and vigilant medical inspection and control of all persons and things arriving in the municipality from infected places or which from any cause are liable to communicate contagion. It shall require the isolation of all persons and things infected with or exposed to such diseases.” (Laws of 1893, chap. 661, § 24.)
In April, 1894, there was a large number of cases of smallpox in the city of Brooklyn. The most thickly infected portion of the city was in what was known as the Eastern District, in which district was the plaintiff’s place of business, in the radius of three miles from which, the evidence tends to prove, there were upwards of fifty cases of the disease in the latter part of April and first of May, 1894. The plaintiff was engaged in the express and trucking and carting business, having in his employ -ten or more drivers and several boys, who were engaged in receiving, transporting and delivering various things, packages, articles of merchandise, etc., in and about the city, and other people frequently came to his place for business purposes.
On May 2,1894, Dr. Shelling, one of the inspectors of the health department of the city, called upon the plaintiff at his place of business and requested permission to vaccinate him. The plaintiff refused, and thereupon was informed by the doctor that he would be given twenty-four hours within which to get vaccinated, and that if it was not done the plaintiff would be quarantined. The next day, about three o’clock in the afternoon, the doctor called again *12and was informed by the plaintiff that he had not been and would not be vaccinated. Shortly after a police officer appeared and told the plaintiff that he was quarantined and would have to stay in. The plaintiff remained there until four o’clock on the afternoon of the next day, when, by virtue of a writ of habeas corpus in his behalf, he came into court and was paroled. The hearing had upon the return to the writ resulted in his discharge. The question is whether there was any evidence offered or received which permitted the conclusion that such detention of the plaintiff was justified.
On March 20, 1894, the defendant, as commissioner of health, promulgated rules for vaccination to the effect that all persons who had not been successfully vaccinated within five years should be urged to accept vaccination, and that, in case persons were found who had never been vaccinated, effort should be made to induce them to accept it. The defendant offered in evidence the proclamation of the health commissioner and of the mayor of the city and the president of the Medical Society of Kings County" of date May 4, 1894, which were respectively excluded. By the former the health commissioner, after, reciting that smallpox had been epidemic in the •city for three months, and that there was imminent peril to the public health of the city by reason of the pestilence, and from the further spread of it, declared that the following were necessary for the preservation of the public health from such impending pestilence, and that such measures should be taken : “ First. Thorough and sufficient vaccination of every citizen who has not been successfully vaccinated within such period of time as, in the judgment of the Commissioner of Health, renders such person immune, should be procured.
“ Second. Wherever any person in said city shall refuse to be so vaccinated, such person should be immediately quarantined and ■detained in quarantine until he consents to such vaccination.”
Annexed to this (which was made part of their’s) was the proclamation of the mayor and president of such medical society to the ■effect that they approved of the taking and doing of the measures and acts above declared necessary by the commissioner of health, and they declared that the peril from an impending epidemic of smallpox should be deemed to exist from January 1, 1894, to and includ*13ing the first day of July following, and proclaimed the same to have existed and to so exist for that period.
It has been seen that the power given by statute to isolate a person is dependent upon his infection with, or exposure to, a contagious disease, and if the plaintiff had within a short time been or then was exposed to smallpox within the meaning of that pro'vision of the statute his detention was justified. This was held in the habeas corpus case before referred to. (Matter of Smith, 146 N. Y. 68.) In the opinion of the court there delivered by Judge Geay, it was said that the mere possibility that persons might have been exposed to such disease is not sufficient, but they must “have been ‘exposed’ to it, and that the conditions actually exist for a communication of contagion in order to bring into operation the power to isolate. The meaning of the particular language in the section is, and it should read, that the board of health shall ‘ require the isolation of all persons and things infected with, or who have been exposed to such diseases.’ ” It may be common knowledge that one coming in personal contact with another infected with a contagious disease or occupying the same room with him is exposed to it. But beyond that, whether in a particular case conditions so exist for the communication of the contagion to a person as to render him exposed to the disease may be a question of medical science and skill.
On the part of the defense evidence was given of the existence of smallpox in the city, something of the extent of the disease in what is called the Eastern District of the city; also tending to prove that some of the men in the plaintiff’s service had been in proximity to the place where the persons infected with the disease were, and in the presence of some of the inmates of houses where it existed. This, standing alone, may have had no essential importance. But the defendant offered to prove how many cases of the disease there were there in March, April and May; also to introduce a map indicating the location of the cases existing at the times in question, and to verify it by other evidence; also offered to prove by a member of the medical profession the infectious and contagious character of smallpox; how the contagion of the disease is conveyed; that it is conveyed by the air, absorbed in the respiratory tract; conveyed in clothing and utensils, and by atmospheric contagion, and how long the poison of the disease retains its vitality. This evidence, as the *14offers of it were made, was excluded and exceptions were taken. We think this evidence was admissible. It was offered with the view to putting a hypothetical question to the witness, and such a question was propounded to him embracing a state of facts and calling for his opinion whether the plaintiff was exposed to smallpox, which was also excluded, and when taking exception the defendant’s counsel asked the court whether it was excluded on the ground that it contained any misstatement of fact. The court thereupon remarked that “ it is not a question for an expert.” The view of the learned court evidently was that so far as the fact rested in opinion, founded upon a given state of facts short of what might, by the aid of ordinary intelligence and understanding, be deemed exposure, it would be no more in effect than that the person was liable to take the disease, a mere possibility of such a result. If no more than that, it would be ineffectual for the purpose of the defense, but can that be assumed % The conditions requisite to constitute exposure, and whether those which actually exist, are such as to have that effect, are not necessarily, and may not be, matters within common understanding. They present medical questions, and the effect of them in a given case is the subject of professional opinion. The reasons for the reception of the opinions of experts as evidence, the occasion for it and the purpose, have been so frequently expressed by judicial and text writers that it is unnecessary to repeat them here. ( Van Wycklen v. City of Brooklyn, 118 N. Y. 424; Young v. Johnson, 123 id. 226.)
No consideration is given to the question whether all the facts assumed by the inquiry were warranted by the evidence or were sufficient to constitute a basis for an opinion (as evidence which otherwise may have furnished some facts for the hypothetical question was excluded), since the ruling was upon the ground that evidence of experts was not competent for the purpose for which this was offered. It cannot now be seen what the evidence would have been, or the bearing which it legitimately may have had. The purpose of the defendant’s counsel was to prove actual exposure of the plaintiff to the disease if he could. Notwithstanding the fact that it is not apparent to common understanding upon these facts that such may have been the relation of the plaintiff to it, that does not seem a sufficient reason for the conclusion that it was impossible to *15furnish, by means of medical opinions founded upon such facts, evidence tending to prove that he was so exposed to the disease.
While the proclamation of the mayor and president of the Kings County Medical Society may not have had the significance suggested by counsel, we are inclined to think it was admissible, for the reason, if no other, that at the time it was issued the plaintiff was in quarantine.
This, however, without the fact of actual exposure of the plaintiff to the disease, could afford no legal justification to his' enforced detention by the defendant.
These views lead to the conclusion that the judgment and order should he reversed and a new trial granted, costs to abide the event.
All concurred, except Brown, P. J., not sitting, and Bartlett, J., who concurred in the result.
Judgment and order reversed and new trial granted, costs to abide the event.
Willard Bartlett, J.:I agree with Mr. Justice Bradley that the defendant should have been allowed to prove how many cases of smallpox there were at or about the time the plaintiff was quarantined, the manner in which the contagion of the disease is conveyed, and how long the poison of the malady retains its vitality. Indeed, it seems to me that it was competent for him to give evidence of any fact, whether of scientific, medical or common knowledge, from which the jury could legitimately draw the inference that the plaintiff had been exposed to the smallpox. I entertain considerable doubt, however, as to the propriety of permitting hyjDothetical questions in such a case as this, which call out opinion evidence to the effect that a given series of events constitutes such exposure; and I prefer to limit my concurrence to the grounds which I have stated.