[spoiler] Dr. Lang's cure was accomplished by using Barnabas' "life force" (which I'd assume was his vampirism, since that is basically what was keeping Barnabas "alive") and transferring some of it to Adam. I suppose using one "dead" person to bring another dead person to life, somehow nullified or drained the curse from Barnabas. However, this 'cure' only applied to Barnabas' physical body in the present. Barnabas' body in 1796, 1897 and 1840 was still cursed with vampirism. When Barnabas projected his astral self into the past, his spirit inhabited his body as it was during those time periods - i.e. vampiric. When Barnabas returned to 1969, he was once again human. This human state was short-lived. He became a vampire again in the present thanks to Jeb Hawkes, who returned the vampire curse to Barnabas. In an attempt to escape the curse, Barnabas then entered 1970 PT, but alas he was still a vampire there. In fact Barnabas remained a vampire in the present-day storyline until Angelique lifted the curse in 1840. All this, of course, raises a variety questions and paradoxes about Adam's draining of the curse, Barnabas' astral self vs. his physical self and where they were at any given moment, Angelique's removal of the curse, etc. It gets really confusing. [/spoiler]
