382 VEGETABLE DRUGS 



bones, and the inferior cornua be cut under the third cervi- 

 cal vertebra and the tissues entirely separated, so that the 

 fore part of the frog is connected with the hind part only by 

 the superior columns, then strychnine dropped in the mouth 

 produces tetanic spasm solely in the fore legs. This shows 

 that the cells of the inferior columns only were those affected. 

 Furthermore, it is probable that other centres of the entire 

 spinal tract, including the medulla, are stimulated to a less 

 degree. Thus the respiratory centres, the vasomotor centres, 

 as well as the reflex and trophic centres, are excited ; but 

 the medullary cardiac centre is but slightly, if at all, affected 

 by moderate doses. The cerebrum is not influenced by the 

 drug, as consciousness is retained throughout the period of 

 poisoning until asphyxia supervenes. The muscles and sen- 

 sory nerves are unaffected by any dose of strychnine. But 

 the motor nerves are paralyzed at once by enormous doses of 

 the alkaloid ; or are paralyzed in the later stages of poisoning 

 by less amounts. Therefore, convulsions do not appear at 

 all, or cease when this condition is reached. An experiment 

 performed upon a frog, poisoned with strychnine, in which 

 all the tissues of one hind leg were previously ligated, except 

 the sciatic nerve, showed that stimulation of the intact leg 

 caused spasms only of the ligated leg, since in the latter 

 the motor nerve fibres had not been reached by the drug 

 (because of the ligation), and therefore were not paralyzed 

 as were those in the limb left intact. 



Respiration. — It is probable that strychnine, in thera- 

 peutic doses, is the most reliable and powerful respiratory 

 stimulant at our command. The breathing is quickened and 

 deepened by the stimulating action of the alkaloid on the 

 medullary respiratory centres. 



Organs of Special Sense. — The eye-sight and hearing are 

 rendered more acute by strychnine. 



Elimination. — Strychnine escapes to some extent un- 

 changed in the urine, while a portion of it is converted into 

 strychnic acid. The alkaloid is found in the urine within' 

 half an hour of its ingestion, and is said to be entirely elim- 



