Now, just stabbing a needle into your spine isn't easy work; usually the needle is separate from the syringe for the initial piercing, then the syringe is added once the needle is in place. In the case of Bier, the syringe didn't fit the needle, which meant that, for a significant amount of time, he sat there with spinal fluid squirting out of his back while Hildebrandt tried to jury-rig the syringe. By the time the two gave up, Bier didn't have enough coke or spinal fluid left in his system to completely numb him properly for testing.
"The good news is you can't feel pain. The bad news is I've paralyzed you from the waist down."
Now, an ordinary scientist would have waited until the drug had completely worn off before trying to proceed with the experiment. But not Bier. Hildebrandt volunteered immediately to take his place, and a moderately coked-up Bier consented. Hildebrandt's legs went numb after the injections, and the two celebrated their victory by testing his threshold of pain. First, Bier tickled and poked him. Then the experiment took a considerably darker, more violent turn as Bier ripped the pubic hair off his lab partner and burned his leg with a cigar.
When Hildebrandt swore he couldn't feel anything, Bier just started throwing everything at him. He smashed a hammer against his knee, punched his balls, pinched his nipples and kicked him in the shins, which we're sure are all legitimate steps in any scientific experiment, particularly one where both scientists are still reeling from injecting cocaine into their cores. Yet throughout the entire experiment, Hilderbrandt felt nothing.
That's the whole of Hildebrandt's legacy. Being punched in the balls.