XI. B, 1 de la Paz and Garcia: Use of Apomorphine 53 



Protocol 7. December 22, 1915. Male dog, 9.05 kilograms. 



11.15 a. m. The tracheal cannula was inserted. The dog was allowed to 



recover from the ether anaesthesia. 

 1.34:80 p.m. The tracheal cannula was connected to a glass tube with an 



opening of about 1.5 millimeters in diameter. 



3.35 p.m. The dog lay quietly on the floor. There was slight dyspnoea, 



but unnoticeable cyanosis (in the tongue). Apomorphine 

 hydrochloride (0.1 cubic centimeter of a 2 per cent solution 

 per kilogram) was injected intramuscularly. 



3.36 p. m. Nausea was observed. 



3.36:30 p.m. The dog vomited. At 3.37, 3.37:30, and 3.38 he vomited 



again, once each time. 

 3.39 p. m. The dog was chloroformed. 



When nonanaesthetized dogs are asphyxiated by shutting off 

 the air from the trachea, retching commonly occurs within the 

 first three minutes without the administration of apomorphine; 

 except in rare cases, the animals die without vomiting. It 

 appears that the vomiting center shares, with the other medul- 

 lary centers (respiratory, vasomotor, and vagus), the transient 

 stimulation followed by paralysis brought about by asphyxia. 

 In three intramuscular injections of apomorphine hydrochloride 

 (0.1 cubic centimeter of a 2 per cent solution per kilogram of 

 body weight) into three normal dogs, the interval between the 

 injection and the onset of vomiting averaged two minutes and 

 twenty seconds, and in no case was it shorter than two minutes 

 and twelve seconds. The absence of vomiting in experiments 

 1 and 5 does not necessarily indicate that the vomiting mecha- 

 nism (center, nerve fibers, nerve endings, or muscles) was par- 

 alyzed within two and a half minutes of respiratory obstruction. 

 We have observed in another animal that the femoral pulse 

 was reduced from 78 to 48 beats per minute and became weaker 

 and irregular at the end of the first minute of almost complete 

 tracheal occlusion. It is, therefore, possible that sluggish cir- 

 culation occurred very early in experiments 1 and 5 and that 

 emesis would have taken place had apomorphine reached the 

 vomiting center in the usual time. Although the vomiting 

 mechanism is readily thrown out of function by complete as- 

 phyxia, it is interesting to note that in partial asphyxia, such as 

 is produced by reducing the tracheal opening to 1.5 millimeters 

 in diameter, it not only survives two hours, but it appears more 

 irritable and consequently responds more quickly to apomor- 

 phine, as was observed in experiment 7 and in two other 

 experiments. 



