614 LEWELLYS F. BARKEK 



exceptional instances he observed acceleration of gastric digestion in 



tetany cats. ' 



The retarded digestion in experimental tetany is not due, Carlson 

 asserts, to the absence of appetite secretion, nor to splanchnic inhibition, 

 but is rather the effect either of the direct action of chemical substances 

 in the blood upon the digestive glands, or of an alteration of activity 

 dependent upon the absence of the parathyroid secretion. 



Carlson maintains further that the deviations from normal activity 

 in parathyroid tetany in cats and dogs, as far as the other sympathetic 

 and autonomic mechanisms are concerned (visceral sympathetic, pilo- 

 motors, sweat nerves, uterus, bladder, sphincters), is in the direction of 

 depression rather than of excitation. It is obvious, therefore, that more 

 studies should be undertaken before these discordant results of observa- 

 tions in human tetany and in experimental tetany can be satisfactorily 

 explained. 



Trophic Disturbances in Chronic Tetany 



In chronic tetany interesting dystrophies, especially of structures of 

 ectodermal origin, are common. Thus, the nails, the hairs, the teeth 

 and the crystalline lens may all exhibit signs of trophic disturbance. 



Nails. Herard (184-3) described a patient, 36 years old, with severe 

 tetany, who shed his finger nails ; and Meinert observed falling out of 

 the nails in tetania gravidarum in a washerwoman. Ewald described 

 falling of the nails in a case of tetany associated with dilatation of the 

 stomach. Hoffmann saw a single finger nail fall out in a case of child- 

 hood tetany. Similar observations have been made in other forms of 

 tetany. Brittle nails, grooved nails, and necroses of the roots of the nails 

 have all been mentioned as occurring in cases of tetany. 



Hairs. Falling out of the hair has been several times met with in 

 chronic tetany. Fortunately, the hair sometimes returns after the at- 

 tacks of tetany have passed off. A Dutch observer, Bolten (b) (1917), has 

 recently described a case of latent tetany in which the hair of the head, 

 the eyebrows, and the body hair fell out. He looked upon the loss of hair 

 as a trophoneurosis due to the latent tetany. General clefluvium of the 

 hairs may, of course, occur in conditions other than tetany. 



Teeth. Most remarkable alterations in dentition in early life, aa 

 well as peculiar enamel defects in the teeth in later life, have been 

 observed in tetany. 



Thus, in rats, the experimental tetany produced by Erdheim (e) ran a 

 very chronic course, the animals surviving operation for from two to 

 five months, or even longer. These animals were found to show constant 

 changes in their teeth, namely, circumscribed enamel defects, sometimes 

 so marked that the teeth easily became fractured. The changes in the 

 teeth in these rats interfered so much with the mastication of food that 



