304 PROFESSOR C. R. MARSHALL ON 



very susceptible to the action of ether. When the cerebrum is intact, ether appears 

 to be less active in arresting convulsions. Even with fairly deep anaesthesia, clonic 

 convulsions are produced by relatively small doses of tutin ; and after large doses of 

 tutin the convulsions do not cease when the concentration of ether inhaled is increased, 

 until shortly before the respiration is paralysed. As will be shown later, when one 

 cerebral hemisphere is excised the injection of moderate doses of tutin causes 

 convulsions only on the same side ; and since the mid-brain and pons are still intact 

 in this experiment, it would seem as if the ether had prevented the development of 

 the convulsions from this part of the brain. 



The effect of diminishing the quantity of ether administered has been observed in 

 experiments in which the contractions of individual muscles were being recorded. 

 To take an example. With a certain concentration of ether vapour the contractions 

 of the Tibialis Anticus were fairly uniform, and registered 3 mm. in height. After 

 reducing the concentration of ether vapour about 40 per cent., the contractions assumed 

 a more convulsive type in twenty-seven seconds, and many at thirty seconds registered 

 27 mm., and at fifty seconds 35-40 mm. in height. The weaker ether inhala- 

 tion was continued for sixty-six seconds, when the concentration was raised to its 

 previous level. The contractions commenced to diminish in eighteen seconds, and 

 in forty seconds they had almost reached their previous form. This occurred twelve 

 seconds later. 



The effect of chloroform on the convulsions was not graphically recorded, except 

 indirectly in tracings of the respiration by Head's method ; but from these and other 

 experiments it appeared to be more powerful, for apparently the same degree of 

 anaesthesia, than ether in arresting the convulsions. 



Muscles Affected by the Convulsions. 



A few experiments were made to determine the way in which various individual 

 muscles are affected by the administration of tutin. They were undertaken primarily 

 with the object of determining the cause of the bizarre positions and curious movements 

 which sometimes occur after tutin. In the experiments the contractions of the 

 following muscles were registered : — Digastric, Mylohyoid, muscles of pinna of ear, 

 Biceps, Triceps, Flexor Carpi Radialis, Flexor Sublimis Digitorum, Extensor Communis 

 Digitorum, Rectus Femoris, Gracilis, Tibialis Anticus, Extensor Longus Digitorum, 

 Flexor Longus Hallucis, Plantaris, and Diaphragm. The muscles of the shoulder 

 and hip were not isolated, but their movements were registered in several experiments 

 by more distally situated muscles which had been isolated. The movements of the 

 muscles of the abdominal wall and the prevertebral muscles were observed but not 

 registered. So far as could be determined, all the voluntary muscles of the body are 

 influenced by tutin, although not simultaneously. The muscles were isolated from 

 the surrounding tissues as far as possible without disturbing their blood and nerve 



