The phenomenon you described in the 1930s was most likely due to the presence of radium-based paint used in watch dials during that time. Radium emits a faint glow, and if dogs were exposed to this substance, their feces could have exhibited a similar effect.
However, the use of radium-based paint was discontinued due to its radioactive properties and associated health risks. Nowadays, watch dials are typically coated with non-radioactive materials like phosphorescent compounds or tritium gas, which do not produce the same glowing effect.
Therefore, you don't see glowing dog feces anymore because the specific circumstances that caused it in the past no longer exist.