572 
a. Z. BARNES. 
all the varieties, but when not used in this sense, it implies 
that the disease involves all classes of muscles equally. When 
the muscles of mastication are alone involved, it is called 
trismus ; when it chiefly affects the superior cervical and dor¬ 
sal muscles, causing the head to be elevated and the spine 
curved downwards, it is called opisthotonos; when the muscles 
of one side are affected it is called tetanus lateralis .” 
I believe, for all practical and scientific purposes, tetanus 
should be classed into two varieties: acute, and sub-acute, or 
chronic. 
Acute tetanus is in my experience always due to some 
traumatic injury, though it might occur from idiopathic 
causes. 
The symptoms of the acute form are always well defined. 
There is usually a difficulty in chewing and swallowing, stiff¬ 
ness of the neck and limbs, tail elevated, protrusion over the 
inner part of the eye of the membrana nictitans, manifested 
on the least disturbance, and marked nervous excitability. 
Temperature and pulse not much affected at the beginning of 
the attack, but in the acute form as the disease progresses a 
marked increase in temperature is noted, and the pulse be¬ 
comes quick and hard when the spasm affects the muscles of 
the heart, or rapid and feeble when it relaxes. All the symp¬ 
toms in the acute form become rapidly aggravated until the 
jaws are completely locked, all the muscles are rigid in a 
state of tonic spasm, a cold perspiration breaks out on the 
body, and if the animal be suddenly disturbed the superficial 
muscles will be seen to twitch and tremble. Death usually 
takes place in from one to five days, either by complication of 
the pulmonary structures, asphyxia; from exhaustion, as a 
result of protracted and severe muscular rigidity and fre¬ 
quency of convulsive attacks; or from hyperpyrexia, associ¬ 
ated with an elevation of temperature to such a degree that 
the organic functions of the heart and lungs are impaired and 
finally cease. 
The sub-acute or chronic form differs from the acute in 
that the symptoms of the attack are more insidious and less 
marked, although nearly all are observed; in some, however, 
