472 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
is of interest to note that the fluorine analogue of chloroform, namely 
fluoroform, is neither anesthetic nor toxic. 
ETHYLENE 
After the discovery of chloroform there followed several barren 
decades in the field of general anesthesia and at the turn of the century 
the armamentarium of the anesthetist contained only nitrous oxide, 
ether, and chloroform augmented in a small measure by ethyl] chloride, 
Through the first two decades of the present century no substantial 
gains were made. However, in 1922, ethylene was introduced by Luck- 
hardt of the University of Chicago. It had been observed that traces 
of ethylene caused the fading of flowers and this observation had come 
to Luckhardt’s attention. He was curious about it. He wondered what 
effect ethylene would have upon animal protoplasm. Systematically he 
tested the gas on lower animals and observed its anesthetic effects. 
Ascending in the scale of development, he observed that the anesthetic 
properties held for monkeys and finally he permitted himself to be 
anesthetized many times to unconsciousness and ethylene took its place 
among the general anesthetics. Perhaps this discovery illustrates the 
characteristics of a scientist, “one who has the simplicity to wonder, the 
ability to question, the power to generalize and the capacity to apply.” 
High concentrations of ethylene are required to produce anesthesia 
(85 to 90 percent) and, to avoid hypoxia, the gas must be administered 
with oxygen. The gas mixture is extraordinarily explosive, and many 
tragic accidents have occurred owing to the explosion of the gas 
through ignition by static electric sparks. Undoubtedly this has mili- 
tated against the widespread use of the gas in many places. 
AVERTIN 
In 1927, Willstitter prepared a general anesthetic, tribromethanol, 
marketed and employed as avertin, dissolved in amylene hydrate. 
The principle involved in this discovery is based upon the theory of 
narcosis announced by Meyer and Overton in 1900. Essentially this 
theory holds that the greater the oil/water solubility is, the more 
potent is its activity on the central nervous system. Alcohol 
has anesthetic properties. The alcohols of the aliphatic series of hy- 
drocarbons of higher molecular weight such as amyl and octyl alcohols 
are less water soluble and more oil soluble, and their potencies as 
anesthetic agents are greater than that of ethyl alcohol. In avertin, 
three of the hydrogen atoms of the ethyl alcohol molecule having a 
combined atomic weight of 3 have been replaced by three bromine 
atoms, the sum of whose atomic weight is approximately 240. This 
increase in molecular weight increases the oil/water coefficient and 
simultaneously enhances the anesthetic potency of the compound. 
Avertin is administered rectally. Its anesthetic index or safety mar- 
