Experiments with intravenous anaesthesia were undertaken in 1872 using chloral hydrate. The high mortality rates discouraged further experimentation until the early 20th Century. Thionembutal, or Pentothal Sodium, was one of these early developments. This ampoule has "Experimental" stamped on it. It has come directly from the manufacturing process. Pentothal Sodium is its trade name. It is now more commonly known as thiopentone.Glass ampoule of Pentothal Sodium (Thiobarbiturate No. 8064) 1.0 gm with large yellowed white label.Printed in black ink on label: Experimental / A 512738 / Abbott Laboratories / North Chicago. Ill., USA.pentothal, sodium, thionembutal, thiopentone, experimental, drugs, intravenous, anaesthesia, anaesthetic, john lundy, ralph waters