The income of such moneys shall be collected annually and one-fourth of the same be added to the principal for reinvestment and the remaining three-fourths shall be used as a fund to be loaned to students of the university, to be repaid at such interest as may be fixed, in cases only where the same may be needed by any student endeavoring to acquire an education, and the methods and terms of making such loans shall be fixed by rules adopted by said board of curators.