172 THE DUCTLESS GLANDS 



As we have already seen, the effects can be induced in an 

 animal from which the central nervous system ha", been 

 completely removed. 



So far as the haemodynamic effects of adrenal extracts are 

 concerned, the papers of Oliver and Schafer gave an accurate 

 account of all the fundamental facts, and there is little or 

 nothing to add to their account up to the present time. 



It had been shown by Gourfein and by Cybulski that adrenal 

 extract in sufficient dose paralyzes the vagus (see Figs. 39 and 

 43). This was confirmed by Langley. The paralysis is brief. 

 In the cat 5 to 10 c.c. of 1 per cent, extract of dried adrenal 

 cause, as a rule, paralysis for from thirty seconds to one or 

 two minutes. When a dose is given a little short of that 

 required to make stimulation of the vagus ineffective, the 

 respiratory curves disappear, and there is a gradual fall of 

 pressure. This result is probably due to weakening of the 

 heart-beat without much variation in rate. 



According to Oliver and Schafer, injection of extract in the 

 dog after section of both vagi causes only quickening of the 

 heart-beat. In the cat Langley found that after section of 

 the vagi adrenal extract sometimes causes quickening only, 

 but that sometimes the rate is irregular, and in one case the 

 heart stopped for three minutes. The slowing, when it occurs, 

 is, Langley thinks, due to the increased work thrown upon the 

 heart ; whether the action is entirely direct on the heart muscle 

 or is partly due to a post-ganglionic axon reflex, there is hardly 

 sufficient evidence to show, but the slow beats caused by the 

 extract are fewer or absent after injection of nicotine, although 

 the rise of blood-pressure is commonly higher. 



As pointed out by Oliver and Schafer, the extract does not 

 act equally on all the arteries ; its effect is perhaps greatest 

 upon those of the splanchnic area, and its action in general 

 runs parallel with the action of the sympathetic nerves on the 

 bloodvessels. Thus, injection of adrenal extract causes great 

 pallor of the uterus and but little of the bladder. It has a 

 strong action on all skin arteries and on all medium-sized 

 arteries in the body. In the abdominal viscera its effect is 

 great on the main branches of the cceliac and superior 

 mesenteric arteries. 



The primary effect of adrenal extract on the vessels of the 

 submaxillary gland is constriction. The gland becomes pale 





