Sci-Fi Movie/Show Where a Soul is Captured in a Glass Vessel

Question

I remember very little of this, I was quite young - It was on television in the mid 90's, but seemed older. My wife was telling me about the 21 grams experiment and the memory clicked into place.

Setting
Inside of a mad scientist sort of lab, with the plasma balls and everything else, a character (Who in my mind resembles Gene Wilder in Young Frankenstein) is conducting an experiment. The room is hazy, lots of hues of purple and red. He has an assistant present. They were conducting some sort of experiment to try to figure out the secrets of immortality (or possibly reanimation). I remember them "trapping" a human soul in a glass vessel to see what it weighed or what kind of volume it took up - I believe they shot someone in this vessel, and because their soul could not "escape", they did not die.

Answer 1

This is The Asphyx (1973)

While filming a public execution as a protest against capital punishment, Cunningham activates a spotlight that he has crafted using phosphorus stones beneath a drip irrigation valve. Later, when viewing the film with his ward, Giles, Cunningham sees that the condemned man's asphyx was briefly held suspended in the spotlight's beam. Concluding that an individual's asphyx is an organic force and therefore subject to the laws of physics, Cunningham theorises that some property of the energy released by the combination of phosphorus and water renders the asphyx immobile. If correct, this would mean that an asphyx could be trapped, and that an individual would be immortal so long as their asphyx remained imprisoned.

Giles and Cunningham successfully capture the asphyx of a dying guinea pig and seal it in the family tomb, beneath a spring fuelled by the lake. Seeing immortality in his grasp, Cunningham tasks Giles with helping him to capture his own asphyx, deciding that his contributions to science are too important for him to die. Cunningham commissions the construction of an impenetrable vault door on his family tomb, with a complex combination lock as the only means of opening it; once he has captured his asphyx, Giles is under instruction to seal the asphyx inside, so that no one can ever set it free.

Answer 2

I was also reminded of Soul Hunter. Especially reminiscent is the detail about capturing the souls in a glass vessel. The Soul Hunter carried his captured souls in glass globes.

Answer 3

Sounds a lot like the 2009 film Cold Souls but I could be wrong, because you said 90's.

Civilization and its discontents. Paul, an actor preparing for "Uncle Vanya" on Broadway, is mired in ennui. His agent tells him about an office where he can put his soul in storage. He does so then discovers that being soulless helps neither his acting nor his marriage; he returns to the office and rents, for two weeks, the soul of a Russian poet. His acting improves, but his wife finds him different, he sees bits of the borrowed soul's life, and he's now deep in sorrow. He wants his own soul back, but there are complications: it's in St. Petersburg. With the help of Nina, a Russian who transports souls to the U.S., he determines to get it back. Who has he become?

Trailer