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of Edinburgh , Session 1868 - 69 . 
determine, accurately, the character of these convulsive effects, to 
ascertain the dose necessary for their production, and to differentiate, 
as far as possible, the structures on whose affection they depend. 
Soon after a small fatal dose, or one rather less than fatal, of a 
salt of atropia is administered to a frog, a slight degree of weakness 
occurs in the anterior extremities, the respiratory movements of 
the chest cease, and the motor power becomes gradually more and 
more impaired, until, at length, all voluntary and respiratory move- 
ments cease, and the animal lies on the abdomen and chest, in a 
perfectly flaccid state. If the condition of the heart be now exa- 
mined, it will be observed that the cardiac impulse is scarcely 
perceptible, and that the contractions are reduced to a very few in 
the minute. At this time, the application of various stimuli shows 
that the functions of the afferent and efferent nerves and of the 
spinal cord are retained, though in a greatly impaired condition. 
Several hours afterwards, it may be on the following day, the action 
of the poison is still further advanced ; for the functions of the 
afferent and efferent nerves and of the spinal cord are completely 
paralysed, while only an occasional and scarcely perceptible cardiac 
impulse can be discovered, the only signs of vitality being this 
imperfect cardiac action and the continuing irritability of the striped 
muscles. This state may last for many hours or for several days — 
in one experiment it continued for as many as five days. Previous 
observers have apparently mistaken it for one of death, and have, 
therefore, failed to observe the symptoms that subsequently appear, 
and to which I wish more particularly to draw attention. The first 
of these symptoms is, usually, a change that occurs in the flaccid 
condition of the animal ; the anterior extremities becoming flexed, 
and gradually more and more arched, until, at length, they are 
rigidly contracted, while tonic spasm occurs in the muscles of the 
chest also. At this time, a touch of any portion of the skin increases 
the tonic spasm of the anterior extremities and of the chest muscles, 
and causes some slight spasmodic movements in the posterior ex- 
tremities. In varying periods after this, the respiratory movements 
reappear, and the cardiac impulse improves greatly in strength and 
in frequency, while the posterior extremities assume an extended 
position, with the webs stretched. If the skin be now touched, a 
violent attack of opisthotonic tetanus occurs, which may last for 
