Dear SilkMuse: what a figure of speech: "a hotbed of vented spleen". Reminds me of ludicrous visual image conjured up by a pathology lecture long ago, about frequent occurrence of gangrene of the legs caused by a fungus infection of the spikes of wheat used to make bread - ergotism. The prof said "Europe was a hotbed of gangrenous legs". I had the visual image of a hot bed containing a couple dozen legs, blackened and enpurpled by the ergot poisoning having interrupted blood flow in arteries, but still writhing about obscenely.
Spleens can be ruptured by severe blow over the spleen. In South Asia when malaria there was untreated, many people had enlarged spleens, so fragile that a common method of murder was to hit victim over spleen with a club. I can't imagine what product would be of incubating spleens in a hotbed.
All said in jest, not to needle SilkMuse.