_Liability to Pay for Services._—An important matter for physicians and surgeons is the question as to who is responsible, or liable to pay for their services. If there is an express contract this question does not arise; but in most instances the person performing the services renders them upon call, and it is necessary for him to understand his legal right to recover pay for services in the absence of an express contract. _Person Treated, and not Person calling in Physician, Employs Him and is Liable._—In the first place, it must be stated as a general proposition that the person for whom the services are actually rendered, or upon whom the operation is performed, is bound to pay for them, if otherwise capable in law of making contracts and incurring obligations. And secondly, that one who calls a physician or surgeon to attend a patient is not presumed to have contracted to pay for the services rendered, unless his relations with the patient are such that he would be obligated in law to pay, even if he had not himself called in the medical man. In the first case it is presumed that the patient is liable, because he receives the benefit of the services, and nothing less than a distinct understanding that he was not to pay will relieve him from this obligation. _Married Women and Infants Generally Not Liable._—Where such a person is a married woman, unless the case arises in States or countries where married women have been declared by statutes to be liable the same as if single, this rule does not obtain. Nor is an infant personally liable when he is living with his parent or guardian. Hull _v._ Connelly, 3 McCord (S. C.), 6; Klein _v._ La Amoreaux, 2 Paige Ch., 419; Atchinson _v._ Bruff, 50 Barb., 384; Wilcox _v._ Smith, 26 Barb., 341. But the contract of an infant for medicine and medical attendance is deemed a contract for necessaries, and will be held valid and enforced against his estate if there is no person standing _in loco parentis_ who can be held liable. 3 Barn. & Cress., 484; 2 Kent Com., 236. In cases when the parent of the infant or the husband of the married woman is liable, this liability obtains because the services rendered are deemed necessary, and fall within the common-law obligation of such persons to provide and pay for necessaries for those whom they are bound to support and maintain.