PRODUCED BY ATROPIA IN COLD-BLOODED ANIMALS. 453 



attacks ceased first in the posterior extremities, continuing for several seconds 

 longer in the anterior extremities and thorax. During the intervals the anterior 

 extremities were constantly flexed by tonic spasm in their muscles, and in those 

 passing to them from the thorax (especially in the pectoralis major). If the skin 

 were touched, or if the frog were otherwise gently stimulated, an attack of empros- 

 thotonic tetanus followed, during which the flexion of the anterior extremities was 

 rendered more rigid, and the posterior extremities were extended and consider- 

 ably abducted. These attacks of tetanus lasted for about five seconds, when the 

 posterior extremities became flaccid ; but the increased spasm of the anterior 

 extremities and of the chest muscles continued for about sixty seconds longer. 

 When the frog was not suffering from general tetanus there were occasional 

 respiratory movements of the throat and chest. It was now impossible to observe 

 any cardiac impulse, because of the constant spasm of the chest muscles. 



On the sixth day — one hundred and sixteen hours after the administration — 

 the frog was lying on the back with the anterior extremities rigidly retained in 

 the position already described ; but the head was bent forwards (downwards) by 

 spasm of the anterior abdominal and chest muscles, and the posterior extremities 

 were loosely extended, with the webs slightly stretched. The respiratory move- 

 ments of the throat were frequent, but those of the thorax but rarely occurred. 

 If a posterior web were now touched, a pretty powerful attack of tetanus followed, 

 during which the body was curved in the form of an arch, with the head bent for- 

 wards, while the anterior extremities were strongly clasped against the chest, 

 and the posterior rigidly extended in a straight line. This was general for about 

 six seconds, when the posterior extremities became flaccid ; but the increased 

 spasm of the muscles of the anterior extremities and of the anterior surfaces of 

 the abdomen, chest, and throat continued for twelve seconds longer. Still more 

 powerful and prolonged tetanus could be excited by stimulating the skin of the 

 head; and these attacks lasted for eight seconds in the posterior extremities, and 

 for two minutes in the anterior extremities and in the muscles of the anterior 

 surface of the chest. So powerful was the tetanus at this stage that it was possible 

 to lift the frog by the feet and hold it horizontally for eight seconds, with either 

 the back or front of the animal uppermost. The faintest voluntary movements 

 almost invariably excited a tetanic convulsion, and, indeed, such attacks could 

 be produced even by excitations through the organs of vision, as by the sudden 

 approach of any object. 



The frog remained in this remarkable condition, without any notable change, 

 until the fourteenth day. 



At this time— three hundred and ten hours after the administration — it still 

 continued in the position last described, but, although violent tetanus could still 

 be excited, this did not occur so invariably as before. Frequently, indeed, 

 excitation produced only slow and stiff movements of the posterior extremities, 



VOL. XXV. PART II. (J A 



