1. There can be no doubt, that in an action on a policy of insurance, the burden of proof is on the plaintiff to show that at the time of the loss he had an insurable interest in the property covered by the policy. This is a fact essential to the plaintiff’s right of recovery, the proof of which lies on him in all stages of the case. 2 Greenl. Ev. §§ 376, 378. But in the present case it does not appear that the question of interest was seriously in dispute between the parties at the trial. Certainly no instruction was asked by the defendants on any matter which necessarily involved a ruling in regard to it.

The real question in contention was, whether the plaintiff had alienated or changed the title to the property, within the meaning of one of the conditions of insurance attached to the policy, and thereby rendered the contract void. This presented a very different issue from that raised by a denial of the plaintiff’s insurable interest in the property, and would require very different evidence to sustain it. It would not have disproved an insurable interest in the plaintiff, to show that after the date of the policy she had transferred the goods, so that at the time of the fire she was only a mortgagor, having a right of redemption in the property, or that she had conveyed it, retaining in herself only a qualified right as pledgor or cestui que trust. Such a title would have been sufficient proof of interest in the plaintiff; but proof of these or similar facts would have been adequate and decisive evidence to show that she had changed the title of the property, and thereby violated a condition on which the *434validity of the contract depended. Such a defence was strictly in avoidance of the plaintiff’s claim. It admitted the existence of a title originally sufficient to sustain the contract; but set up a new and distinct fact, in the nature of a condition subsequent, which, if proved, would defeat the plaintiff’s right to recover The burden of proof was therefore on the defendants to estab lish it. They assumed the affirmative of this issue, and were bound to prove it.

2. To constitute a breach of the condition of insurance relating to a conveyance of the property, there must have been an actual sale or transfer of property, valid as between the parties. A change of title was necessary to invalidate the contract. Perhaps it was not material to prove that the transfer was absolute ; nor that it conveyed the whole right of the plaintiff in the property; nor that it was a valid conveyance as to creditors. But it was essential that there should have been at least the form of a transfer. Under the instructions given on this point, the jury must have found that there was not even a formal alienation of the property. ■ Judgment on the verdict