106 ENDOCRINE GLANDS 



the labial commissure, causes a sudden contraction of the 

 muscles of the commissure and those of the side of the 

 nose, sometimes even one-half of the face. This is 

 Chvostek's sign. Weiss's sign is analogous: percussion 

 performed on the superior branch of the facial at the 

 level of the external angle of the orbit causes a contraction 

 of the frontal muscle and those of the eyelids. 



(b) Investigation of the electrical excitability gives 

 the following reactions: 



1. Galvanic hyperexcitability of the nerves and 

 muscles and the possibility of obtaining muscular con- 

 tractures on the closure of the Cathode with a current of 

 loss of 1 milliampere. This is what has been termed 

 Erb's sign. 



2. Hyperexcitability at the anodal opening current and 

 predominence of the contraction on opening instead of a 

 closing as normally occurs. 



3. Hyperexcitability at the Cathodal opening and the 

 possibility of obtaining opening contractions with a current 

 of less than five milliamperes. 



These reactions are characteristic of tetany. 



(c) Accessory Symptoms. The reflexes are often 

 exaggerated. Sensory disturbances are missing, except in 

 very severe cases, which are accompanied by cramps and 

 sharp stabbing pains. There are no sphincter disturb- 

 ances outside of retention of urine from spasm of the 

 sphincter. The temperature is usually normal except 

 in very severe cases. The examination of the cerebro 

 spinal fluid does not show any evidence of meningitis. 

 In certain chronic cases vaso motor disturbances may 

 occur: indurated edema of the back, of the hand, or of 

 the foot, redness or cyanosis of the extremities, or of the 

 face and during the attack trophic changes; falling out of 

 the hairs, brittle nails, etc., as in experimental tetany. 



