224 Thompson 



confirmed by Hoogenhuyze and Verploegh (1905) (15). After severe 

 muscular work, in a condition of absolute fasting, the excretion of 

 urinary creatinine was increased. The same was also observed (1910) 

 in mountain climbing when the oxygen supply was deficient. Ordinary 

 muscular exercise produced no effect. 



Pekelharing (1911) (16), who assigns a special function to creatine 

 in connexion with muscular tonus, found an increased excretion after the 

 muscles had been kept tonically contracted for long periods — for example, 

 in the maintenance of the military position. 



It does not, however, follow that an increased output in the urine after 

 muscular work necessarily implies a reduction of creatine in the muscles. 

 The contrary may happen, as in starvation. Thus it has been shown by 

 Demant (17), and more recently b}^ Mendel and Rose (18), that when 

 animals are starved the creatine content of the muscles is increased, at all 

 events relatively, notwithstanding a simultaneous excretion of creatine in 

 the urine. An absolute increase in the muscles is, however, improbable. 



In studying the direct effects of activity on the creatine of muscles, 

 attention has not always been paid to simultaneous variations in the 

 content of water. Ranke (19) found an increase of water in tetanised 

 muscles. This has been confirmed by many subsequent observers, including 

 Danilewski (20), Wortz (21), Ganike (22), and Barcroft (23). To be 

 certain, therefore, of a variation in any of the solid constituents during 

 the activity of muscle, it is essential to ascertain the content of water 

 in it and allow for alterations if they have occurred. 



In the following investigation this was kept in view. Cats were em- 

 ployed, the animals being anaesthetised and decerebrated according to 

 Sherrington's method. Care was taken to prevent loss of heat by 

 enveloping the head in cotton-wool and by pinning a layer of felt round 

 the body. A hot- water can was also let into the operating table on which 

 the animal was placed. 



The muscles of the right leg were removed immediately after decere- 

 bration and used for comparison with those of left. The anterior crural 

 and sciatic nerves on the left side were divided and armed with shielded 

 electrodes after removal of the muscles of the right side. The nerves on the 

 left were excited for periods varying from two to two and three-quarter 

 hours. The excitation was intermittent, each period of one-minute 

 stimulation being followed by a pause of two-minutes rest. 



In removing the limb muscles, a line of stout sutures was laid along the 

 flexure of the thigh, passed through the limb from front to back. Before 

 tightening these, an elastic bandage was placed on the limb from below up. 

 After the sutures were tied and the elastic bandao-e removed, the skin over 

 the thigh muscles was divided and reflected as far down as the heel. The 

 muscles were then stripped from off" the bones of the thigh and leg and 

 the limb amputated at the knee joint. Cotton- wool was then wrapped 

 round the femur, and over this the skin replaced. In this way any slight 



