12 card set, average condition is VG/EX. Wrapper is similar to a bank wrap rather than a wax wrapper. The artwork for the original printing of this set was done by Lynne Bogue Hunt and Mary E Eaton. The set was reprinted through the 60's but with different art. The artwork on these is all done by Doris M Cochran, which would indicate that this is a later print run.. We can't narrow it down to which printing however, as Cochran's career as a scientist and a scientific illustrator spanned 40 years.