Wilson and Gisvold, pgs.
Anesthetics are depressant drugs that produce a partial or total loss of the sense of pain .
In the case of general anesthetics , this is accompanied by a loss of consciousness . The first demonstration of such a drug was conducted in 1844 by Samuel Cooley, who demonstrated the effects of nitrous oxide on a Pharmacy student. This is the type of anesthesia referred to as twilight sleep . Stage II - this stage is characterized by a loss of consciousness . It is also a critical period, since delerium and increased involuntary activity, as well as hypersecretion , can occur.