376 PROCEEDINGS OF THE ACADEMY OF 



ment, there is, on the contrary, a steadily progressive stage of 

 spinal depression. 



Complete paralysis of the spinal cord is the last effect of a 

 poisonous dose of conia, for the instant that the cord ceases to re- 

 spond to galvanism, respiration ceases and death occurs. 



Action on the Periphery of the Efferent Nerves. To discuss 

 this subject is really to discuss what has long been considered and 

 beyond a doubt is the chief symptom of hemlock-poisoning; 

 namely, paralysis. The cause of this paralysis has occasioned 

 great dispute among investigators since 1835, when Christison 

 (loc. cit.) announced that it was due to paralysis of the spinal 

 cord ; this was denied by Albers (Deuts. Klin. 1853, No. 34), who 

 believed it to be "due to the action which conia has on the brain." 

 Reuling and Saltzer (loc. cit.) and Van Praag (loc. cit.) agree 

 with Christison in attributing the paralysis to the action on the 

 spinal cord. 



The first person who threw any real light on the subject was 

 Kolliker (Virchow's Archiv, Bd. x. S. 228). In 1856, this dis- 

 tinguished investigator announced that the failure of motion in 

 conia-poisoning is due to a direct action of the alkaloid upon the 

 periphery of the efferent or motor nerves. He first experiment- 

 ally proved that in frogs killed by conia the application of the 

 galvanic current to a nerve fails to induce contractions in the 

 tributary muscles. He then cut off the supply of blood to the 

 hind extremities, and found that after voluntary motion had 

 ceased anteriorly, and even after galvanic irritation of the ante- 

 rior nerves had lost its influence upon the muscle directly sup- 

 plied by these nerves, irritation of the same anterior nerves caused 

 reflex contractions in the posterior extremities, thus showing that 

 the anterior afferent nerves and the spinal cord still retained 

 functional activity after the loss of it in all those efferent nerves 

 reached by the poison. He then extended his experiments by 

 severing in a frog all the tissues at the upper part of the thigh 

 except the nerve, and found that when an animal so prepared was 

 poisoned by conia, after the paralysis was complete in all the ex- 

 tremities to which the poison had access after stimulation of 

 the poisoned nerves failed to excite contractions in the tributary 

 muscles the leg which had been protected from the action of the 

 drug, responded not only to irritation applied to its nerve, but 

 also to stimuli placed upon distant portions of the body. After 



