212 DRS. T. L. BRUNTON AND J. T. CASH ON CHEMICAL CONSTITUTION, 
From these experiments it appears that amongst the drugs contained in the table, 
the most marked disturbance occurs in the Fat in the case of the ethyl-ammonium 
sulphate, amyl-ammonium sulphate, amyl-ammonium iodide, diethyl-ammonium- 
sulphate, diethyl-ammonium chloride, triethyl-ammonium chloride, and tetra-methyla- 
mine ammonium iodide. In all of these tremors were noticed, and in some—the 
diethyl-, triethyb, and amyl-ammonium salts—a peculiar rapping of the head upon the 
table was noticed, which appeared to be of a convulsive character. 
The two most powerful convulsants were the amyl-ammonium-sulphate, and the 
tetramethyl-ammonium-iodide. 
We found that the iodides not enumerated amongst those causing marked nervous 
disturbance have little tendency to produce spasmodic movements. In them loss of 
reflex, first in the hind legs, and then in the anterior part of the body, is most marked. 
It appears to us that as a group the salts of the compound ammonias have a 
complex action : they affect the spinal cord, motor nerves, and muscles. The extent 
to which these structures are affected by the different compounds varies with each 
compound. 
The spinal cord appears to be first stimulated, and then paralyzed. The symptoms 
which lead us to suppose that it is first stimulated are the twitchings which occur in 
the early stage in Rabbits and Rats, when poisoned with the substances mentioned in 
the tables, and the convulsions which occur in Frogs poisoned by ethylamine and 
tetraethylamine-iodide. That the spinal cord is paralyzed at a later stage, both as a 
conductor of motor stimuli and as a reflex centre, we infer from the failure of reflex 
action both in Frogs and Mammals, and from the fact that a stimulus applied to the 
hind foot frequently induces motion, not of the corresponding hind leg, but of one of 
the fore legs. 
The convulsions which occur shortly before death in mammals are, perhaps, to 
be regarded as due, not to the irritant action of the poison on the nerve centres, but 
rather possibly to its paralyzing action on the motor nerves : this motor paralysis 
causes enfeebled breathing, and a consequent venous condition of the blood with 
asphyxial convulsions. That the compound ammonias and their salts paralyze the 
motor nerves is shown by our direct experiments on the nerve muscle preparation, in 
which the nerves were almost always paralyzed before the muscle. The muscles, 
however, are by no means unaffected—at first their power may seem to be increased, 
so that they respond by a more powerful contraction to irritation; afterwards, 
however, they become weakened, and tend to become completely paralyzed by the 
continued action of the poisons. This increase of irritability is not observed in the 
case of some of the compounds, even as a temporary condition. 
