In Iowa, a physician who had treated a patient for injuries was not allowed to testify whether his patient told him that the car on which he was injured was in motion at the time, because as the injury would be likely to be more severe if the car was in motion, that information was necessary to enable the physician to prescribe.[417] In Michigan, a physician was allowed to contradict his patient as to when her trouble commenced, in the absence of evidence that such information was necessary to enable him to act.[418] Where a physician was asked whether he treated a person for typhoid fever, and he answered that she was not so diseased, it was held that this information was not necessary to enable him to act.[419] And the same was held to be true where a physician examined a prisoner at the jail and testified that he was diseased, the prisoner having been notified at the time of the examination that it was made by direction of the prosecuting attorney and there being no intention to prescribe or act for the prisoner.[420] But it has been stated that all disclosures by a patient to a physician respecting ailments are privileged whether necessary to enable the physician to prescribe or not.[421] In Minnesota, a physician was allowed to disclose statements as to suffering made by his patient, but not for the purpose of enabling him to prescribe or act.[422] In Missouri, it has been said that information as to the way in which an injury was inflicted is of the greatest necessity for successful treatment; and that it is information which physicians universally demand and receive.[423] In another case, with reference to the cause of a patient’s condition, it was said that while knowledge of the cause may not be necessary, the disclosure of the cause cannot be made without a disclosure of the condition, and that as a medical person cannot tell indirectly what he is forbidden to tell directly, the physician’s evidence of the cause is inadmissible.[424] In another case it was said that any information, necessarily coming to a physician in order to treat his patient, is to be regarded as necessary information though unimportant, and that the test is how it was acquired, not whether it could have been acquired in a different way, and therefore it was incompetent for a physician to testify that his patient was drunk when he treated him.[425]