[ 19 ? ] 
VIII. Contributions to our knowledge of the connexion between Chemical Constitution, 
Physiological Action, and AntagonismA 
, By T. Lauder Brunton, M.D., F.P.S., and J. Theodore Cash, M.D. 
Received June 13,—Read June 21, 1883. 
[Plates 8-10.1 
The great object of Pharmacology is to obtain such a knowledge of the relation 
between the chemical constitution and physiological action of bodies as to be able to 
predict with certainty what the action of any substance will be. One of the most 
important steps towards this object was made by Crum-Brown and Fraser, who 
showed that the introduction of methyl into the molecule of strychnia or thebaia 
changed the tetanising action of those poisons on the spinal cord into a paralyzing one 
on the ends of the motor nerves. 
As the organic alkaloids are compound ammonias, it seemed probable that a similar 
change in the chemical constitution of ammonia itself might produce a corresponding 
change in physiological action. This was tested by Crum-Brown and Fraser, who 
found that trimethyl-ammonium iodide possessed a paralyzing action similar to that of 
methyl strychnia or methyl thebaia, while ammonia itself has been shown by Funke and 
Deahna to have a tetanising action very much like that of strychnia. A number of 
other ammonium compounds have been shown to have a similar paralyzing action; but 
there is no complete investigation of the whole series, nor has the relation of the acid 
with which the base is combined been determined. 
In the present research we have attempted— 
1st. To ascertain how the general action of ammonia is modified by its combination 
with an acid radical. Under this heading we have investigated : (a) the alteration 
in its general effects upon the organism ; and ( b ) the alterations in muscle and nerve 
by which the general effects are to a great extent determined . 
2nd. To investigate the general action of the compound ammonias containing the 
more common radicals of the alcohol series in the same way as the ammonium 
salts in the first part of the paper. 
* The present research forms part of an investigation into the action of certain drugs on muscle and 
nerve, for which a grant was given to one of us (Brunton) in 1877, hut the prosecution of which was 
touch delayed by various circumstances, amongst others, the rebuilding of the laboratory in which the 
experiments were made. 
