210 STIMULANTS TO PERIPHERAL NERVES 



to its anthelmintic properties. Some claim that it is a vermicide for 

 both tape and round worms and recoinmend it per os for dogs affected 

 by these parasites. I have injected a solution of the drug into a loop 

 of the intestines and after several minutes found living tapeworms in 

 the loop. It frequently expels worms, however, but whether this is 

 due to active peristalsis or direct action upon the parasites is not 

 clear. 



Respiratory System. Moderate, doses slow the respirations by 

 stimulating the vagus. The caliber of the bronchi is reduced by 

 stimulation of the nerve endings of their plain muscles. Dyspnea 

 results and is particularly marked if the animal is affected with 

 heaves or other respiratory trouble. In such cases the symptoms may 

 be dangerously aggravated. Large doses produce death by respira- 

 tory paralysis. 



Circulatory System. Arecoline is a distinct depressant to the 

 circulatory system. Moderate or therapeutic doses slow the pulse by 

 stimulation of the vagus and lower blood pressure. Toxic doses 

 produce arythmia of the heart, great fall in blood pressure and ac- 

 celeration of the heart. The last mentioned condition is due to vagus 

 paralysis. The heart usually continues to beat after the respirations 

 cease. 



Secretions. These are in general increased, due to a stimula- 

 tion of the nerve endings in the glands. The sweat, urine, nasal and 

 bronchial secretions are increased together with those of the digestive 

 tract. 



Eye. Local applications are followed by an increase of tears, 

 spasm of the lids and some hyperemia of the bulb. This is soon fol- 

 lowed by a constriction of the pupil, which begins in about 5 minutes 

 after its application, reaches its mininium in 10 minutes and after 

 about 10 more begins to dilate and returns to normal in about 70 

 minutes. This action is not seen after the internal use of the drug 

 and in the dog I have seen widely dilated pupils from large sub- 

 cutaneous doses. 



Toxicology. Frohner gives the toxic dose for the horse at 3 — 4 

 grains and the fatal dose at 7% grains, but the author had one horse 

 recover from 10 grains. In this case, however, antidotal doses of 

 atropine were given immediately after salivation began. In a few 

 experiments made upon dogs it appeared that after previous injec- 

 tions of small doses, the fatal dose was thereby apparently increased. 



The symptoms of poisoning are : slow, weak pulse ; marked fall in 

 blood pressure, marked salivation, cyanosis, sweating, slowed and 

 shallow respirations and dyspnea and collapse with a fast arythmic 

 pulse. The antidote is atropine, which paralyzes those structures 

 stimulated by arecoline. This should be given subcutaneously. 

 Atropine should not be administered with arecoline, because in this 

 case the period of action of arecoline is too short to be of any benefit. 



