I dissent.
Where as here the grazing preferences and privileges had already been established, the duties of the directors of the grazing district in allocating such preference rights for the years 1950, 1951, 1952 and 1953 were simply ministerial.
Courts do not control the discretion of the district Board nor of the Commission, but we have the authority and it is our duty and responsibility to see to it, when brought to our attention, that the discretion of the Board and Commission is exercised within and in accordance with the state law.
The grazing preferences set forth in Chapter 23 of Title 46, R.C.M. 1947, are valuable rights; they shall run with and be *220appurtenant to the dependent commensurate and commensurate real estate property upon which they are based. Since the rights here in question had been established and had become appurtenant to the real property of the plaintiff Burke, prior to the years 1950, 1951, 1952 and 1953, the district or the Grass Conservation Commission may not legally reduce permanently the plaintiff Burke’s established grazing rights. It became the mandatory duty of the Board and the Commission to allot the grazing preference rights under the provisions in that regard provided in Chapter 23 of Title 46, B-.C.M. 1947. See State ex rel. Engle v. District Court, 119 Mont. 319, 324, 325, 174 Pac. (2d) 582.
This court in Langen v. Badlands Co-operative State Grazing Dist., 125 Mont. 302, 234 Pac. (2d) 467, did not pass upon the pertinent question pertaining to established rights raised ini this case, hence that decision has no application to the specific question raised.
Since our duty is so plain and simple, it is not my intention to dwell on this matter at any great length. In my opinion two-inconsistencies are glaringly present in this record. The inconsistencies concern matters of vital importance to all stockmen having established preference rights in such districts.
The full consideration of these facts in my opinion proves the plaintiff’s contention that the Board and the Grass Conservation Commission both abused their respective discretion.
The first of these is this: The Carnahan ranch at the time that the larger unit was sold to the Town Brothers had an appurtenant preference grazing right of 320 animal units. There is no evidence that that preference was ever reduced prior to such sale. On May 22, 1950, the minutes of the district reveal that the portion of the Carnahan ranch sold to the Town Brothers had 223 animal units. Burke also bought his portion of the Carnahan ranch in May of 1950. The purchases by the Town Brothers and Burke constituted purchases of the entire Brothers and Burke constituted purchases of the entire Carnahan property. Thus in May 1950 the Town Brothers’ portion carried *221223 units, Burke’s portion therefore carried the difference between 320 and 223, or 97 animal units.
Yet the Commissi on contends this is not so, that because of deterioration Burke’s portion represents only 43 animal units. The Commission contends further that the reduction is necessary and proper because of deterioration of the Carnahan ranch property. At the same time however that they permanently reduced Burke’s preference rights they gave the Town Brothers’ portion of the Carnahan ranch its full share of preference units without any deduction at all. This determination by the Commission to reduce Burke’s appurtenant valuable grazing preference rights, and not reduce the Town Brothers, was arbitrary and an abuse of discretion. If the reclassification for deterioration purposes was to be made, it was not proper nor legal to confine such reclassification to Burke’s portion of the entire ranch unit and omit the Town Brothers’ portion. There is no evidence in the record that the entire Carnahan ranch was reclassified; lacking such, the abuse of discretion is obvious.
The second irreconcilable fact, in regard to the law, was in regard to the testimony of the Forest Service employee. He was allowed to assert that because of “common practice” certain property was to be classified as “self-furnished range” and that therefore the owner of such property would have his preference reduced. Yet he blandly testified that the land, Burke’s portion, so classified as “summer range” is so classified purely from practice, without regard to the actual prior use of the land. In essence, he says, when the land use is changed we consider it a reduction from summer grass land, whether or not the land was summer grass land or not.
The Commission in basing their findings and conclusions upon such testimony has acted without the law and in an arbitrary, capricious and unlawful manner. This court in my opinion should never affirm a determination of an administrative body founded upon arbitrary and illegal “common practices.”
I would reverse the order of the district court and order the Grass Conservation Commission to enter an order giving the *222plaintiff the 97 animal unit grazing- rights appurtenant to his land and of preference to which he is entitled, on the record made in this case.