§ 172-e. Construction of article. This article is not to be construed as applying to any substance, subject to this article, sold at wholesale or retail for use by a retail druggist in filling, or in dispensing in pursuance of, a prescription by a physician, dentist or veterinarian; or for use by or under the direction of a physician, dentist or veterinarian; or for use by a chemist in the practice or teaching of his profession; or for any industrial or professional use or for use in any of the arts and sciences.