I'm trying to understand some paper about Udagawa Youan and chemistry in Japan and I have a big problem with 殺素. It's means all chemistry elements which can kill or mayby only radioactive? Or mayby it's means something else? And is this word in use today too?
Example from paper:
榕菴初期の気体化学、窒素と殺素、大気に濛気の語。