BELLADONNA AND ATROPINE 177 



an increase of the output of th^ organ per unit of time. Blood 

 pressure is raised by constriction of the splanchnic vessels, due to 

 stimulation of the vasomotor center, together .vs^ith acceleration of 

 the heart. Simultaneously vi^ith the constriction of the vessels of 

 the abdomen, those of the skin are dilated by excitation of the vaso- 

 dilator center, so that the blood tends to flov? from the deeper vessels 

 to the more superficial parts. The dilatation of the cutaneous ves- 

 sels, however, is insufficient to counteract the constriction of those of 

 the abdomen, and blood pressure usually rises after therapeutic doses 

 of the drug. Larger doses lower blood pressure immediately by 

 action on the heart and even small doses do so sometimes. The dila- 

 tation of the skin vessels is more especially seen in those of the head 

 and neck, and in man a flushed face or erythematous rash is char- 

 acteristic of atropine poisoning. The heart action always persists 

 after respirations cease, so that heart failure is not considered as the 

 cause of death. 



Respiratory System. Small and therapeutic doses stimulate 

 the respiratory center and render the respirations quicker and 

 deeper, thus increasing the amount of air inspired per minute. Fol- 

 lowing large doses, this quickening is frequently interrupted by con- 

 vulsions, which may cause death. If respiration returns, it is 

 slower and shallower during the stage of depression of the centers 

 and respiratory failure is the cause of death in fatal poisoning. 

 Animals are said to have recovered from six times the fatal dose if 

 artificial respirations were used. In addition to the above action, 

 atropine also paralyzes both the afferent and efferent vagal fibers in 

 the muscular coat of the bronchi, so that this is relaxed and the secre- 

 tions are not so irritating as before. The relaxation of the muscles 

 of the bronchi causes these to dilate and it is probably due to this 

 action that this group of drugs is so serviceable in treating heaves of 

 horses. The secretions of the nose and throat are diminished. On 

 account of the diminished sensation to the entire tract, together with 

 the lessened secretions, cough is lessened. 



Nervous System. Small or therapeutic doses have very little 

 effect, but large ones stimulate the cerebrum and may produce 

 nervousness, restlessness and delirium in man and occasionally in 

 animals, followed by depression and drowsiness. It is not a nar- 

 cotic in therapeutic doses. Convulsions usually occur finally from 

 toxic doses, probably due to asphyxia brought on by cessation of 

 the respirations. 



Glands. All the secretions' are diminished except the urine, 

 milk and pancreatic juice. This action is due to paralysis or depres- 

 sion of the nerve endings in the secreting glands. The action on 

 the mammary glands is explained by Bastedo, in the following man- 

 ner: These glands have the power to secrete milk even after all 

 their nervous connections have been divided. Therefore, atropine. 



