Are there any maker labels or tags on it? What is the history that you know, was a family member a dentist?
It is a seldom seen form, however being late Victorian and done with quarter-sawn oak, it is more likely to be American. This dates to just about 1895 - 1900. The stamped 15 is an assembly piece number and does not lead to a maker name. On today's market, your cabinet can sell for $2500 - $4000 at auction. Here is a link for you of one from the same era in a different form that sold for $2950 in February of this year: http://www.worthpoint.com/worthopedia/wonderful-victorian-walnut-original-1800856399
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