94 



Scientific Proceedings (105). 



ear was moistened with 1 c.c. of commercial xylol in order to 

 produce irritation and edema. 



Two groups of control experiments were carried out. In the 

 first group, each normal rabbit received 10 c.c. of horse serum in- 

 traperitoneally and after 30 to 45 minutes the ear was treated 

 with the same kind and amount of xylol. In the second group of 

 controls no horse serum was administered, merely one ear was 

 treated with xylol. 



The results were strikingly different and support the working 

 hypothesis. In a great majority of the 36 controls edema of a 

 fair to good degree developed in six hours; it was generally less 

 in 24 hours, and after 48 hours had largely disappeared, leaving 

 a practically normal ear. No dermatitis with blisters and crusts 

 was observed; nor were hemorrhages or gangrene seen except 

 once among the controls. In this instance the loss of substance 

 was not more than one half millimeter of the ear tip. 



In the sensitized series (17 rabbits) the edema of the ear de- 

 veloped more slowly and less frequently than among the controls. 

 The maximum was reached generally in 24 hours, and the sub- 

 sidence was slow, lasting 5 to 9 days. Within 22 to 48 hours, 

 numerous small hemorrhages, blisters and subsequent crusts 

 appeared. In these rabbits (10 out of 17) the ear after a few days 

 showed the picture of an exfoliative dermatitis. This dermatitis 

 involved 1/3 to 1/2 of both surfaces of the ear, healed slowly as 

 the deeper tissues were affected, and always caused dry gangrene 

 of the ear tip. The loss from gangrene varied from I to 3 centi- 

 meters. Healing was usually complete in three to four weeks. 

 The ear stump was bald at first, but slowly became covered with a 

 new growth of white hair. 



56 (1516) 



The selective effect of the accelerator nerves on ventricular systole. 

 By C. J. Wiggers and L. N. Katz. 



[From the Department of Physiology, School of Medicine, Western 

 Reserve University, Cleveland, Ohio.] 



Object of Investigation. — Acceleration of the heart in man is 

 chiefly due to a varying balance of control exerted through the 



