delivered the opinion of the Court:

The pivotal question in this case is whether there existed any liability on the part of the landlord to repair the defective radiator. As was said in Iowa Apartment House Co. v. Herschel, 36 App. D. C. 457, we “are not dealing with an ordinary tenancy. The tenancy here relates to an apartment house, — a class of tenancy of comparatively recent origin, and one which, in some respects at least, is to be distinguished from other classes.”

It is a matter of common knowledge and observation that, to quite an extent, this class of tenancy in the larger cities has displaced the old. Instead of a tenement complete in itself and having its own heating facilities, the modem apartment house may contain anywhere from a dozen to a hundred or more so-called apartments, all heated from a main plant operated and exclusively controlled by the landlord. In all the larger houses the landlord also operates and maintains an elevator system for the general aecommo'dation of the occupants of the house. lie controls and keeps in repair common hallways and entrances. In short, the tenant has possession of nothing more than the rooms of his apartment, the landlord controlling everything else. Leases are of course entered into in the light of this common practice and understanding, and, while their positive *256stipulations are absolutely controlling, parol testimony may be introduced when it is apparent that the written instrument does not express the whole agreement of the parties. Naumberg v. Young, 44 N. J. L. 331, 43 Am. Rep. 380; Potter v. Easton, 82 Minn. 247, 84 N. W. 1011; Lillard v. Kentucky Distilleries & Warehouse Co. 67 C. C. A. 74, 134 Fed. 168.

In the light of the foregoing observations, was it error to admit the testimony as to the conversation preceding the signing of the lease ? !>The lease, as we have seen, is entirely silent on the subject of heating. It is equally silent as to what constituted “Apartment No. 43.” The evidence showed that this apartment was provided with steam radiators and with no other heating means; that these radiators were part of the steunheating plant constructed in the building, and over which the defendant retained exclusive control. That the radiators were in the apartment for practical, and not ornamental, purposes is apparent, for the evidence shows that heat was supplied through that means. Supposing nothing whatever had been said concerning heat, could it have been successfully contended, in view of the circumstances just detailed, that the plaintiff would have been without redress had the defendant neglected or refused, after the commencement of the tenancy, to heat the apartment ? We think not. There is nothing in the lease concerning elevator service, nor is there anything therein concerning the duty of the defendant in respect to the halls and entrances to the building, and yet, under the decisions, all these things were implied incidents of the tenancy. Thus in Sawyer v. McGillicuddy, 81 Me. 318, 3 L.R.A. 458, 10 Am. St. Rep. 260, 17 Atl. 124, the defendant was the owner of a building on the second floor of which were several tenements occupied by different tenants and having a common stairway. It was held that the defendant, in the absence of an express agreement to the contrary, was charged with the duty of caring for and maintaining this stairway. In Shipley v. Fifty Associates, 101 Mass. 251, 3 Am. Rep. 346, a tenement building was leased to different tenants under leases requiring them to make repairs. It was held that, inasmuch as the possession of the *257roof was in the owners, they were under obligation to repair it. So, in Looney v. McLean, 129 Mass. 33, 37 Am. Rep. 295, it was held that a landlord who lets rooms in a building to different tenants, with a right of way in common over a staircase, is bound to use reasonable care in keeping such staircase in repair. The court, after stating the general rule that a tenant takes the premises as they are, said: “But this rule applies only to premises which, by the terms of the lease, have passed out of the control of the landlord into the exclusive possession of the tenant.”

Had this suit grown out of a failure on the part of the defendant in respect to an implied covenant regarding hallways or elevators, parol evidence would have been admissible, — not to vary the terms of the lease, but to annex an incident. We think such evidence clearly admissible for the purpose of proving what was really covered by the terms of the lease.

Under the authority of the Iowa Apartment House Case, 36 App. D. C. 457, the obligation to furnish steam heat carried with it the duty of providing and maintaining means for the proper fulfilment of that obligation. The implied covenant to keep this heating system in repair carries with it the right on the part of the landlord to enter the premises at reasonable times for the purpose of fulfilling that obligation. Such a control of the premises on the part of the landlord is not inconsistent with the possession of the tenant as the owner of the particular estate during the tenancy. Miles v. Janvrin, 200 Mass. 514, 86 N. E. 785.

It is next contended that the plaintiff was guilty of contributory negligence as matter of law. In the first place, the plaintiff was not a steam fitter, and, in the second place, there is no evidence in the record that anyone not possessing some knowledge of such matters would have had reason to anticipate the sudden enlargement of the defect in the radiator. The plaintiff himself testified that he saw no crack until after the radiator was taken out, and did not, until that time, know the nature of the defect. He repeatedly directed the attention of the defendant’s agent to the leaky condition of the radiator, and they *258promised to have it repaired. Defendant’s janitor, who was in charge of the entire heating system, and presumably much more familiar with radiators and their defects than the plaintiff, did not even suggest the imminence of a greater break or the necessity completely to turn off the steam. Nor a whole month the precautionary measures taken by the plaintiff had been sufficient. He was to be away for two days only. While the evidence shows the janitor had no key to the apartment, it does not show that the agent did not have one. It does not even appear that the plaintiff knew that the janitor was without a pass-key, but, aside from that, we do not think the conduct of the plaintiff, in the circumstances, was such that reasonable men would be bound to say he was negligent. The question was carefully submitted to the jury under a prayer prepared by the defendant. This was all the defendant could ask.

The next and last question relates to the measure of damages. There was ample evidence before the jury from which it might have found that the defendant, through his agents, had reason to believe that the defect in the radiator, if not repaired, would be likely to produce the results of which the plaintiff complains. Having exclusive control of the heating system, it was incumbent upon the defendant to exercise due care in maintaining that system and keeping it in repair. What would constitute negligence on the part of the agent charged with the immediate control and supervision of this system might not, for the reasons previously suggested, constitute contributory negligence on the part of a tenant. The failure of the defendant, after knowledge of the defect, to repair it, coupled with knowledge of the consequences reasonably likely to ensue, constituted negligence, and rendered the defendant liable for the damages immediately resulting from such negligence.

The case relied upon by the defendant, Thompson v. Clemens, 96 Md. 196, 60 L.R.A. 580, 53 Atl. 919, is not in point. That was an action for personal injuries growing out of an alleged failure on the part of a landlord to make certain general repairs of premises under the exclusive control of the tenant. The damages in such a case are much more remote and consequential. *259The court, however, ruled that a landlord “may under some circumstances be liable for damages for personal injuries by reason of a negligent failure to make repairs.” In Massachusetts it has been held that there can be no recovery for personal injuries against a landlord, even for negligent failure to make repairs, unless the landlord has assumed the duty of looking after the condition of the premises and providing for their safety for the protection of the tenant. Miles v. Janvrin, 196 Mass. 431, 13 L.R.A.(N.S.) 378, 124 Am. St. Rep. 575, 82 N. E. 708.

The plaintiff in the case under consideration is not seeking damages for personal injuries growing out of the failure of the landlord to make general repairs, but is asking to be reimbursed for the actual damages suffered as the immediate consequence of defendant’s negligence in failing to repair an instrumentality under the exclusive control of the landlord.

Judgment affirmed, with costs. Affirmed.