PHYSIOLOGICAL ACTION, AND ANTAGONISM. 
221 
difference between the paralyzing action of the corresponding chlorides and sulphates. 
In the case of the muscle we notice that the irritability is increased, as a rule, in 
poisoning by the chlorides; is sometimes increased and sometimes diminished by the 
sulphates; and, as a rule, though with some exceptions, it is decreased by the iodides. 
The contractile power of the muscle, as shown by the extent and duration of tetanic 
contraction on direct stimulation, appears to be least affected by the chlorides; some¬ 
what more so by the sulphates ; and most of all by the iodides. The alterations 
in the form of the curve have already been described in detail. 
Variations amongst the Ethyls and Methyls. 
The least operative compounds examined were the diethyls and triethyls. Thus, in 
these alone, in the case of the iodides and sulphates, w T as minimal irritability equal to 
or greater than the normal. 
(a.) In the case of the chlorides, however (in which the ethyls, methyls, di- and 
trimethyls only were examined), there was not a material difference between the 
corresponding compounds. 
( b .) Amongst the iodides there is a strong tendency to loss of irritability of the 
nerve with all the compounds, but this is pre-eminently the case with the tetraethyl- 
and tetramethyl-ammonium iodides, /which have an extremely powerful paralyzing 
action. The methyl compounds appear, however, to be operative in a slightly 
smaller dose. 
(c.) The smaller group of the chlorides does not present such striking variations, 
but the corresponding methyls are slightly more active than the ethyls. 
(d.) Amongst the sulphates we find the ethyls more often to produce an exaggerated 
single curve and an increased tetanus than do the methyls. There may, however, as 
shown in the chart of trimethyl-ammonium sulphate, be an increase in tetanic con¬ 
traction as a result of stimulation in an early stage of poisoning. 
(e.) The methyl compounds of the sulphate group are decidedly more fatal to 
the irritability of the nerve than are those of the ethyls. 
(/.) Ethylamine showed development of tetanic spasms 70 m after injection. There 
was a gradual failure of reflex and circulation. 
There was increased irritability to both direct and indirect stimulation; the curve 
was higher, longer, and showed increased viscosity. 
Triethylamine —gradual failure of reflex and of circulation. Increased viscosity of 
the muscle was observed, without a marked lengthening of the curve. 
Trimethylamine —gradual failure of reflex and of circulation. Increased irritability 
and increase of viscosity. The curve is equal to or shorter than the normal. 
The methyls are more active than the corresponding ethyls. The methyls, amyls, 
and ethyls are more effective than the corresponding di- and tri- compounds. The tetra 
compounds are, however, most so of all. 
