OF THE CALABAR BEAN. 785 



muscles that when the secondary coil is slowly advanced contractions will occur 

 with the same current in both muscles, or with a weaker current in the case of 

 the poisoned than in that of the non-poisoned one, this varying with the length 

 of time which has elapsed since the limb was deprived of blood ; when the current 

 is transmitted through both nerves, contractions will be produced simultaneously 

 in both muscles, or with a weaker current in the non-poisoned one, or con- 

 tractions will occur in the non-poisoned muscle only, this also varying with the 

 length of time that may have elapsed since the exhibition of the poison. 



8. In mammals and birds, the voluntary muscles are affected in a very 

 remarkable manner. At an early stage of the poisoning, faint twitches occur, 

 which gradually extend over the body, and, at the same time, increase in vigour 

 so as to interfere with the respiratory movements. Shortly before death, they 

 again become mere successive twitches, often requiring the use of the hand 

 to discover their existence. After death, if a muscular surface be exposed, 

 these twitches will still be observed, involving usually different muscular fasciculi 

 at different times, rarely the whole of a muscle at once ; and in mammals they 

 may persist for more than thirty minutes after death. They are caused by a 

 direct effect of physostigma on the muscular substance. This is shown by their 

 continuing after paralysis of the motor nerves, by their persisting in a muscle cut 

 out of the body, and by their non-occurrence in parts that have been separated 

 by ligature from the circulation. 



9. In mammals and birds, when the dose is large, the heart's action is rapidly 

 made slower and then stopped. In dogs, it may diminish to one-half in three 

 minutes, and cease in ten. In frogs also, a large dose, injected into the abdominal 

 cavity, causes rapid and complete cardiac paralysis. A smaller dose causes 

 either a gradual cessation followed by a renewal at a diminished rate, or a gradual 

 fall, from sixty or seventy to four or six beats per minute, followed by a gradual 

 return to a diminished rate of from eight to twenty per minute. At this stage, 

 and for many hours afterwards, the only signs of vitality are this diminished 

 cardiac action and the power of the voluntary muscles to respond to galvanic and 

 other stimulation. In the frog, where alone these last phenomena have been 

 observed, the heart may continue so to contract for three or even five days, pro- 

 vided the temperature of the apartment be as low as 50° F. After stoppage, 

 galvanism may sometimes cause a renewal of rhythmical contractions ; but this 

 can rarely be done, and unrhythmical and partial contractions can alone be 

 excited. Cessation of the heart's contractions occurs in diastole, with all the 

 chambers full. 



10. The pneumo-gastric nerves retain their inhibitory power over the heart 

 during the whole time from the diminution to the partial recovery of its action. 

 Soon after this, however, they are paralysed ; and this occurs at nearly the same 

 time as the affection of the motor nerves. 



