538 MECHANISM OF SECRETIOX OF GASTRIC JUICE. 
efferent impulses, dilator in character, passing along the sympathetic to 
the mucous membrane. 
That impulses passing along the vagi influence the movement of the 
stomach, and possibly by that means to some extent the secretion, has 
been shown by several observers. 
Goltz 1 exposed the stomach and oesophagus of two curarised frogs, 
and, after suspending them, dropped into their mouths salt solution. One, 
however, had had the brain and spinal cord destroyed. After a time it 
was found that in the complete animal the stomach and oesophagus were 
widely distended, whilst in the pithed frog they were empty. The latter 
result occurred equally well if the vagi only were cut. Stimulation of 
the vagi peripherally caused only slight contractions. The explanation 
given by Goltz of this result is that the stomach walls presumably 
contain a local mechanism which, under the conditions in which the 
animals were, would have undergone stimulation. The result of this 
would have been peristaltic contraction, causing the fluid to be passed on 
into the intestine. But ordinarily this is controlled by efferent impulses 
passing from higher centres along the vagi. If the controlling influence 
is destroyed, there results an exaggerated action of these centres. Goltz 
was disposed to regard this local mechanism as of a ganglionic nature. 
In connection with this question, it may be stated that Openchowski 2 has 
described the existence of special nerve-plexuses with ganglionic cells, both at 
the cardia and at the pylorus. He considers that the opening and closing of 
these passages are to be referred to the direct influence of these ganglia, though 
these again are under the control of the central nervous system. Openchowski 
describes a centre for the contraction of the cardia situated in the posterior 
corpora quadrigemina, and connected with the stomach mainly by the vagi. A 
centre for the opening of the cardiac orifice lies in the basal ganglia, and 
communicates with the stomach by means of the vagus. There are also 
subsidiary centres in the spinal cord influencing dilatation of the cardiac 
orifice. In the same regions are centres influencing movements of the pylorus 
and the intermediate walls of the stomach. Openchowski emphasises the 
antagonism between the movements of the cardia and the pylorus ; such nervous 
impulses as proceed down the vagus and dilate the cardiac orifice simultaneously 
close the pylorus. 
As regards the more direct influence of impulses proceeding along 
the vagi upon secretion in the stomach, for a long time the greatest 
uncertainty prevailed, and it was held that in general such impulses did 
not directly affect secretion, but merely indirectly, through promoting 
movements of the stomach walls. Heidenhain 3 has suggested that, as 
mechanical irritation produced secretion from the digestive glands in the 
plant Droscra, so the direct irritation of food in the stomach might 
stimulate the gastric epithelium. There has existed for a long time, 
however, indirect evidence of a flow of gastric juice resulting from 
psychical conditions. Bidder and Schmidt i noticed, as early as 1852, that 
the sight of food in a gastrostomised dog resulted in an abnormal flow of 
gastric juice. To obviate any possibility of swallowed saliva causing 
this result, which saliva it was known could be secreted as the con- 
1 " Studien liber die Bewegung von Speiserohre und Magen d. Frosche," Arch. f. d. 
ges. Physiol., Bonn, 1872, Bd. vi. 
2 "Ueber die nervosen Vorriehtungen des Magens," Centralbl. f. Physiol., Leipzig u. 
Wien, 1889, Bd. iii. 
s Hermann's "Handbneh," Leipzig, 1881, Bd. v. Th. 1. 
4 ; 'Die Verdauungssafte und der Stoffwechsel," Leipzig, 1852. 
