This is an advertising ink blotter for Cal-C-Malt, a 1930s health product that contained calcium phosphate, vitamin B, vitamin C and diastatic malt. Apparently you could mix it with milk, which doesn't sound terribly tasty.
It was claimed that the product could build resistance against infection and give you "sound teeth, improved appetite [and] robust health." (As opposed to run-of-the-mill health, I reckon.) While that's not too boastful, I wonder if it's veering a bit close to Maść Żywokostowa Ucco Salve territory.
Here are a few tidbits about the product I found with a Google Books search:
- It was referred to as a "swell chocolate drink" in a circa 1937 issue of American Druggist. The full issues aren't available online, but I could see these snippets: "Why can't I take my vitamins like Jimmy Smith? He gets a swell chocolate drink -- Cal-C-Malt. He let me taste some the other day and, oh boy, was it good! ... Since Jimmy started taking Cal-C-Malt, he's not nearly so susceptible to colds."
- From a 1942 edition of Roche Review: "At that time, this preparation was called Cal-C-Malt 'Roche.' The vitamin C content of Cal-C-Malt was 50 mg per serving, equivalent to about three-fourths of a glass of orange juice. In 1938, the name of Cal-C-Malt was changed to Cal-C-Tose."
- According to a 1938 issue of Hospital Management, the name was changed "as a safe-guard against possible confusion of the product with other preparations featuring the term 'malt'."
- I cannot find the full text, but it appears there was a 1939 Federal Trade Commission ruling regarding Hoffman-La Roche Inc. and its advertising of Cal-C-Malt.
Here's a link to an image of a different Cal-C-Malt ink blotter.