None.
This "card" Woodward made for his mother was part of a collection of papers, photographs and other items given to the Smithsonian Museum, and is found in their collection. The handwritting suggest he was quite young. The back of the card is dated 1904, but we believe this to be incorrect. Woodward would have been 19 years old by that year. Given the handwritting still being very child-like, we believe he was most likely under the age of 10, which would make the year 1894 when he was 9 the more likely time period.