On behalf of the Commissioner the contention was made that if the deed be construed as intending an assignment it should be held to have been ineffectual on the ground that in respect of the royalties to become payable by Cowen the appellant had no more than a mere expectancy or possibility such as cannot be assigned either at law or in equity: In re Ellenborough [1] . In support of this contention reliance was placed upon the decision which this Court gave in Norman v. Federal Commissioner of Taxation [2] in relation to a purported voluntary assignment of what was described in the relevant deed as the assignor's right, title and interest in and to the interest payable by a firm in respect of a sum of £3,000 being portion of a larger sum that had been deposited by the assignor with the firm and was still outstanding at the date of the assignment. That case, however, stands in clear contrast with the case that is before us. The deposit had been made under an agreement which provided that the firm might repay the money or any part of it at any time without notice, but that the taxpayer should not be entitled to require payment except upon eighteen months' notice. As it turned out, the money was not repaid before the end of the relevant year of income, so that interest in accordance with the agreement became payable and was paid in respect of that year. The interest was held to be the assignor's income, on the ground that the attempt to assign the right to receive it was void as being an attempt to assign, without valuable consideration, property not presently in existence. To understand the ground of decision it is necessary to remember that in respect of the future year the loan agreement recorded the terms which should apply to the relationship of borrower and lender so long as such a relationship should exist, but it left the borrower free to decide whether such a relationship should exist in the relevant year. It gave the lender no right in any possible event to insist upon there being a loan in existence in that year. In the present case the situation at the date of the assignment was exactly the opposite. There existed at that time a contractual relationship between the appellant and Cowen which by its terms must continue throughout the ensuing three years, whether Cowen should wish it to continue or not. The appellant, therefore, had a vested right in respect of those three years. It might indeed become divested, for the licence agreement provided for cesser of Cowen's liability to pay royalties if the letters patent should not be maintained or should be declared void; but the right existed, though it was thus subject to defeasance by events not within the control of Cowen. It is true also that what the appellant's right under the licence agreement would yield in royalties in those years - indeed, whether it would yield any royalties at all in those years - no doubt depended upon contingencies partly within the control of Cowen. It was for him to decide how many castors, if any, he would manufacture in accordance with the appellant's inventions and try to sell. Market conditions would then determine how successful his efforts to sell would be. But whatever he might do or desire to do, the existence of the appellant's contractual right would be unaffected, though the quantum of its product might be. The tree, though not the fruit, existed at the date of the assignment as a proprietary right of the appellant of which he was competent to dispose; and he assigned ninety per centum of the tree. The case is of the general class of which Brice v. Bannister [1] is an example, and may be usefully compared with Bergmann v. Macmillan [2] and Hughes v. Pump House Hotel Company Ltd. [3] .