437 
of Edinburgh, Session 1868-39. 
strychnia. After poisoning with atropia, and during the stage of 
exaggerated reflex excitability, the attacks of tetanus cannot be 
excited by the very slight stimuli which are sufficient to do so in 
strychnia-poisoning. Various irregularities, also, are frequently 
met with in the tetanus of atropia. Some of these have been already 
described, and of the others it is sufficient to mention the occur- 
rence of tonic spasm of one group of muscles in one limb, and of 
another group in another ; of tetanus in the posterior extremities, 
with only slight increase of reflex excitability in the anterior ; and 
of contractions of unequal force in the muscles at the sides of 
the chest and neck, causing lateral curvature during a tetanic con- 
vulsion. 
The numerous experiments that have been made have so far 
solved the problem of the dose required to produce these remark- 
able phenomena, that they may now be almost unfailingly produced. 
Tetanus, or, at least, a state of greatly exaggerated reflex excitability, 
nearly invariably occurs when a dose of the sulphate or acetate 
of atropia, equivalent to the one-thousandth of the weight of the 
frog, is administered by injection, either under the skin or into the 
abdominal cavity. Doses varying from the one eight-hundredth 
to the one twelve-hundredth of the frog’s weight, may also produce 
these effects. The larger doses always produce the most violent 
tetanic symptoms, if they are not fatal during the stage of paralysis ; 
and they may be given with confidence to very small animals, and 
to such as have been kept in a laboratory for several months. The 
smaller doses are best adapted for large frogs, and for such as have 
been recently obtained from their natural habitats. If a dose be 
employed smaller than those above indicated, impairment of the 
functions of the cerebro spinal nervous system and of the heart may 
be caused, but general tetanus will not follow, although spasms 
restricted to certain regions may occasionally appear. The tetanic 
state resulting from the administration of the largest doses usually 
terminates in death, that from the smallest in recovery. 
There are some special difficulties to be overcome in determining 
what structures are concerned in the production of this tetanic 
action of atropia ; for in following the only available plan, that, 
namely, of preventing the poison reaching certain regions while it 
has access to others, it is essential to remember that important 
