When I ran INTERNATIONAL HOUSE (1933) with W. C. Fields and told the audience Cab Calloway singing THAT REEFER MAN was singing about marijuana they got it. If I didn’t, they didn’t: https://www.dailymotion.com/video/x1xls3 .
The same with SWEET MARIJUANA from MURDER AT THE VANITIES: https://www.youtube.com/watch?v=NjdETBXwDo8 , and with Charlie Chaplin snorting “nose powder” in MODERN TIMES: https://www.youtube.com/watch?v=AkLnj5pJtDI . 
If I told the audience before hand they got the gag. If I didn’t, they didn’t.
Those films were and are hipper than far too many realize.
This was at Rochdale College in Toronto in the 1970s when I was Director of Cinema Studies. The Government of Canada allowed within Rochdale the use of hashish LSD, marijuana and mescaline.
It was 18 floors. The higher up we went, the higher we got.