NATURAL SCIENCES OP PHILADELPHIA. 367 



THE PHYSIOLOGICAL ACTION OF HEMLOCK AND ITS ALKALOID. 

 BY B. F. LAUTENBACH, M.D. 



The ancient Greek physicians possessed a more accurate know- 

 ledge of the physiological effects of conium than was acquired by 

 more modern investigators until a comparatively recent period. 

 So late as the year 1845, a well-ascertained and carefully observed 

 case of poisoning by hemlock disclosed truths respecting its tox- 

 ical action which had laid dormant for centuries. An occasional 

 raj 7 of light has indeed appeared to those who from time to time 

 have -sought to determine the properties of the plant : but the 

 general state of our knowledge may be summed up in the words 

 of a very eminent therapeutist. About sixteen years ago Pareira 

 (Elem. Mat. Med., vii.) wrote: "In the present state of uncer- 

 tainty with respect to the real physiological operation of hemlock, 

 it is obviously impossible to lay down indications or contra-indi- 

 cations for its use which can be much relied on." 



Since these words were written a number of investigators have 

 appeared in the field, the majority of whom have been content 

 with studying the most marked symptom of hemlock-poisoning, 

 i. e., paralysis, while a few announced idle theories in regard to 

 its action, which others have again disproved. Reference to the 

 most modern treatises on therapeutics shows that very little, 

 apart from its bare toxical effects, is known of its physiological 

 operation, and the little that is known is involved in such a mass 

 of contradictory evidence as to have led some authorities to 

 ignore it altogether. 



As conia represents the entire active principle of hemlock, I 

 shall confine my observations almost exclusively to it. t 



In man the chief symptom produced, when conia is taken in 

 doses just sufficient to decidedly impress the system, is great 

 muscular weakness; this is accompanied by giddiness, and occa- 

 sionally by disorder of vision. There is an intense desire to lie 

 quiet in a semi-horizontal position, and owing to the heaviness of 

 the eyelids which now occurs, the eyes are kept shut, thus giving 

 rise to the impression that the person is asleep. On attempting 

 to walk the subject's feet feel as though they did not belong to him, 

 and he falls from his knees refusing him support. The pulse is at 



