Sentence:  “From the many' reports that have appeared on the subject it is evident that the '606, or <WSD>'Hyperideal</WSD>,' or whatever other name it may bear by the time these words are published, does not keep well, the injection is painful, and the fever and other signs of a reaction compel vigilant oversight for a few days. 
Meaning of the word marked with <WSD> tags:  A form of salvarsan that was introduced by (Paul Ehrlich), but soon found to be prone to severe side effects.