In the mid 1880's the Brit gun trade began to recognize that a significant part of the shooting population simply were unable to master double triggers. Lock work and bolting were solved and ejectors were making good progress. So, a lot of creativity was turned to single triggers. The actual mechanics behind a workable single trigger is a bit complex and took a good deal of trial and error. Recognition of the involuntary second pull (a reaction to recoil) was key to working single triggers. Many of the early models were, shall we say, "fussy."
I suspect this quote originated with a master speaking to an apprentice in reference to servicing single triggers, "You are a KYrow praktor and I am a New Row surgeon. You don't cut nuttin' unless I say so!"
DDA
