156 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
results were obtained by exposing cortical nerve-cells to vapour of chloroform, or to 
solution of chloral hydrate. 
Neither Binz nor Bernard showed that there was any precipitation or semi- 
coagulation at or near the concentrations which correspond to anaesthesia, nor were 
the optical methods used capable of demonstrating effects upon the protoplasm short 
of precipitation. 
Dubois 1 advanced the theory that anaesthetics produce their effect by a partial 
dehydration of the protoplasm, by increasing the tension of dissociation between the 
water and the tissues, as he put it, so that the latter part with a portion of their 
water, and so tend to approach the dormant condition of dried seeds and other 
organisms in the dehydrated condition. Dubois quotes an experiment in which plant 
tissues on being subjected to the action of saturated chloroform vapour exuded water, 
and compares the effect to that produced by cold. There is, however, nothing con- 
vincing in the experiments, and the transudation of water is more probably due to 
injury of the epidermal cells than to any physical action of the anaesthetic directly upon 
the protoplasm. 
Schmiedeberg, 2 in his Grundriss der Pharmakologie, states that chloroform retards 
the passage of the oxygen from the oxyhaemoglobin to easily oxidizable substances and 
forms a peculiar compound with the haemoglobin, but that these changes cannot be 
proved to take place in the living body. 
Turning from the theories which drive anaesthesia from an action of the 
anaesthetic upon the cell protoplasm to those which, inspired by the large percentage 
of bodies soluble in ether which the nervous system contains, look for an explanation 
to some effect upon the cell lipoids, we find the view advanced by Bibra and 
Harless 5 soon after the discovery of the anaesthetizing action of chloroform and 
ether that these anaesthetics owe their activity to their solvent power for the fatty 
and allied constituents of the nerve cell. 
These authors supposed that the anaesthesia was produced because the 
anaesthetic dissolved out a portion of the lipoid substances, and the experimental 
evidence on which they based this hypothesis was that after repeated anaesthetization 
by ether, analysis showed that the ethereal extractives of the brain decreased in 
amount, while the amount of ethereal extractives in the liver increased. 
It is, however, most probable that this result was due to an experimental error, 
for if there were any actual removal of bodies soluble in ether from the nerve cell, it is 
difficult (i) to see how the removal could be effected by such small quantities of anaes- 
thetic as are required for the induction of anaesthesia acting merely in dilute solution 
in the plasma ; (2) to see how removal of a small fraction of the total lipoid could pro- 
duce anaesthesia ; and (3) to explain if the removal of this small fraction of lipoid does 
I Anaesthetic phyuohgique, 1894, p. 15. 
2. Quoted from the authorized translation by Thomas Dixon, M.B., Young J. Pentland, Edinburgh, 1887. 
3. Quoted trom Overten, Sludien liter die Norkose, S. 50. 
