Ralph Hopkins and Custav Mann, Heat-Coagulation of Muscles of Northern etc. 553 



Method: The muscles were slowly heated in Ringer's fluid (10°/ 

 sodium chloride: 60 c. c; l°/ potassium chloride: 7.5 c. c; l°/ calcium 

 chloride: 10 c. c; l°/ sodium bicarbonate: 10 c. c; in 1000 c. c. of destilled 

 water), while so arranged that any shortening 1 would be recorded on a 

 revolving' drum, on which was also recorded by a signal magnet each rise 

 of one degree of temperature in centigrades. The muscles used were 

 the gastrocnemius and sartorius, further those of the tongue, heart, 

 stomach and urinary bladder. Unless otherwise stated the muscles 

 were subjected to the heating as quickly as possible after dissection 

 from the pithed frogs. With the exception of the heart and the 

 stomach the muscles were used entire. In some instances (specified 

 in the tables) a strip of heart muscle was used instead of the entire 

 muscle, a circle of muscle being cut from the heart just below the 

 junction of the auricles and the ventricles, the circle of tissue being 

 again cut to make a strip. Except in stated instances, a strip of 

 muscle from the stomach was used instead of the entire organ. This 

 was obtained by making an incision through the lesser curvature, 

 peeling off the mucous membrane, and then cutting a strip about five 

 millimeters wide and the full length of the stomach. The bladders 

 were dissected out, emptied of urine, and tied at each upper horn 

 with the threads arranged for recording the shortening. The tongue 

 excised and tied at the two tips and at the base. To record the was 

 shortening of the muscle directly, the lower end of the same was 

 attached to a heavy lead disk in a beaker containing Ringer's fluid, 

 while the upper end was attached to a thread playing over a pulley. 

 This thread having passed over the pulley was tied to a rigid straw 

 about 22 cm. long and the straw had attached to it a recording needle 

 made out of glass. To keep the straw steady a weight of 2 grams 

 was tied to the lower end of the straw. The weight of 2 grams 

 exerted therefore a definite pull on the muscle 1 ). 



When coagulation took place the muscle shortened and the thread 

 attached to its upper end was pulled down and the writing point 

 attached to the straw recorded the contraction by a rise equal to the 



x ) Other experiments with different weights did not seem however to affect 

 the results explained in this paper. 



