Superman
Ultra has recreated the "purple plague" which existed in the middle ages, and has spread it for no apparent reason. It's very deadly--it is described that "people drop right and left on the streets" and "daily, the streets are clogged with death--wagons carting away load upon load of putrifying corpses... horror grips the city!!" A young scientist, Professor Henry Travers, works to develop a cure. His first attempt fails, and he is kicked out of his scientific society. Even the chemical company will no longer sell to him, so total is his disgrace. Superman steals the supplies the man needs, and he proceeds to create a cure. Finally, Superman causes Ultra to be killed by his own ray gun.
The strangest thing about this comic is the absolutely academic tone with which Clark and the professor discuss things. It's all like "oh, yes, I was playing around at curing that horrible plague, but now that I've been kicked out of my science club, I don't feel like trying to save humanity anymore", and then "you'll be reinstated in science club for saving humanity". Really? That's their big concern? It's bizarre!
Also, lots of death, lately: thousands dead in the last Batman comic, then who knows how many in this Superman comic.
Zatara and the Gorilla King
Zatara awakens in a hotel room, faced with a huge roaring gorilla. He changes it into a little monkey, and Tong comes in to see what's the matter. Haven't seen Tong in ages--thought he might have been written out of the comic. Anyway, it turns out that a man, Handers, has been putting human brains into gorilla bodies to have powerful slaves. Zatara resolves to stop Handers.
Eventually, they arrive at a gorilla city, where human slaves are found in chains. Zatara frees and arms them, and they kill the enslaving gorillas. Then Zatara enchants Handers so that he will pull his own city's self-destruct switch, an hour after Zatara and company have left. They leave, the city is blown apart by dynamite, and the day is saved.
This isn't the first comic which has had an intelligent gorilla in it. I think some Speed Saunders comic, perhaps, did, and maybe another. Of course, later on in the DCU, there will be a city of sapient gorillas, as well.