In January, 1936, appellant sold to her  daughter, the appellee, a parcel of land with all the buildings and improvements thereon situated at Nos. 1215, 1217, 1219, and 1221 Juan Luna, Tondo, Manila, in consideration of the sum of P4,000. In civil case No. 49536 of the Court of First Instance  of Manila, which was instituted by the  present appellant against the present appellee in order that the sale be either rescinded or declared subject to the condition presently to be mentioned, final judgment was rendered in which the  court found that the purchase  price  of the house was far  below  its assessed or market value  and  that the sale was subject to the condition that  the vendor shall receive from  the   vendee by  way  of  life pension  one  half of the  rents  from  Nos. 1215,  1217 and  the ground floor of Nos. 1219  and 1221 Juan Luna.  By virtue of that judgment said condition was annotated on the back of the certificate of title:

On  May 3,  1941, without appellee's fault,  the building or  buildings  above  mentioned were totally  destroyed by fire.  Appellee and appellant, however, collected P5,000 and P1,000, respectively,  on the insurance of their respective interests.

After the destruction of the building appellee sought by motion in the land registration case to cancel the annotation  on the certificate of title  of the condition of the  sale above mentioned, on the theory that her obligation to  pay appellant a life pension  had terminated upon the destruction  of the building out  of the rents from which said pension  was payable.  The Fourth  Branch of the Court of First Instance of Manila granted the motion over the opposition of the appellant and  ordered the cancelation of the annotation and the issuance of a new certificate of title in favor of the appellee without such annotation.

Appellant contends  (a)  that her right to receive a  life pension  as  a  condition  of  the sale affected not only  the building but also the lot on which it was erected and, hence, such right was not extinguished upon  the loss of the building ; and  (b) that the proceeds of the fire insurance policy which  appellee collected  should be ordered invested in the construction of another  building.

The trial court believed that the life pension was an incumbrance on the building  alone, and held that said building  having been  destroyed without appellee's  fault,  and there remaining nothing but the lot, "which in Manila  constitutes a liability  when it has no building,"  the life pension could no longer subsist.

It may indeed seem at first blush that the rents out of which the pension was payable were earned by or paid for the building only, independently of the lot on  which it  was erected; but further reflection will show that such  impression is wrong.  When both land and building belong to the same owner, as in this case, the rents on the  building  constitute an earning of the capital invested in the acquisition of both  land and building.  There can be a  land  without a building, but there can be no building without land.  The land, being an indispensable part of  the rented premises, cannot be considered as  having no rental value whatsoever.

Since  appellant's participation in the rents  of the leased premises by way  of life pension was  part  of  the consideration of the sale, it cannot be  deemed extinguished so  long as she lives  and so long as the land exists, because that land may be rented to anyone who may desire to  erect a building thereon.  As a matter of fact, counsel for  the appellee stated in open court during the oral argument that the present motion to cancel the annotation on his  client's title was occasioned by the desire of the  appellee to lease the lot in question to a company which intended to establish a gasoline station thereon but which did not want to enter into the  contract of lease unless the incumbrance or annotation on appellee's title be first canceled.   That, only goes to show  that the land itself has a rental value.  Hence we think it  is erroneous  to hold,  as  the trial court did, that the condition of the sale above mentioned  attached  only to the building  and not  to the land also, both land and building being the subject of the sale.

This is not an action by appellant to compel appellee to fulfil the said condition of the sale by paying her as a pension one half of the rents of the premises  in question.  As long as said premises earn no rents, appellant claims nothing because her  right  depends  upon  the  existence of the rents.  The nonexistence of the rents because of lack of any tenant on the premises cannot produce the extinguishment of  appellant's right.  The destruction of the building did not make the fulfilment of the condition of the sale forever impossible, inasmuch as a part of the subject  of the sale, the land, still exists and may yet be rented.

But even granting  that the obligation of the appellee to pay to the appellant  during the latter's lifetime one half of the  rents  of the building in question or of certain portions thereof is an incumbrance on the building alone, such obligation may properly be considered as  constituting the appellant a co-usufructuary of said building.   Article 469 of the Civil Code provides that usufruct may be created on the whole or  a part of the fruits of a thing, in favor of one or more persons, simultaneously or successively, and in any case from or to  a certain  day,  conditionally  or  unconditionally.

Article 517 reads as follows:

"Art. 517. If the usufruct is  created on an estate  of which a building forms part, and the latter should be destroyed in any manner whatsoever, the usufructuary shall be entitled to enjoy the use of the land and materials.

"The same rule shall be applied if the usufruct be created upon the building only and the latter  should be  destroyed.  But, in such case, if the owner desires to construct another building he shall  be entitled to occupy the ground and to make use of the materials, being obliged to  pay the usufructuary during  the  continuance of the usufruct the interest upon a sum equivalent to the value  of the ground and of the materials."

It is clear, therefore, that from whatever aspect the case is viewed, the conclusion  is inescapable that appellee's  obligation towards appellant under the contract above mentioned has not been extinguished.

We cannot consider here appellant's contention that the P5,000 collected by appellee from the  insurance on  the building should be invested in the construction  of  another building in lieu of the one destroyed by fire so that one half of the rents thereon may be subjected to the payment of appellant's life pension.  That matter is entirely beyond the  scope of the present proceedings under section 112  of Act No. 496, and can  only be determined in an appropriate action.  (Fidelity and Surety Co. vs.  Ansaldo and  Quintos de Ansaldo, 37 Off. Gaz., 1164.)

The order appealed from is reversed and appellee's petition is denied, without any finding as to costs.  So ordered.

Yulo, C. J., Moran, Paras, and Bocobo, JJ., concur.