章 647: Chapter 649: Killed Wu Wanqing

No one knows that she came up with the technique of cowpox vaccination, she hadn't shared this with anyone either. Even if the butterfly claimed that she had revealed it, she could simply deny it adamantly. Moreover, would the butterfly really divulge this?

If it had been the well-known suturing technique in Danliang Country that the butterfly tried to pin on her, it would have been plausible. However, the technique of cowpox vaccination is still a mystery to Danliang Country. It would be surprising if the butterfly chose to reveal it.

Especially since, even though he had the method, he would still need to dedicate resources and energy to research it. He would be even less willing to disclose such a thing.