SMALL INTESTINE. 249 



the other is left open, and fastened into the open wound in 

 the abdomen. The intestinal fluid obtained through this 

 orifice is quite pure ; it is a limpid juice, slightly yellow, very 

 tenuous, and alkaline ; its properties are nearly all negative : 

 it acts neither on starch nor on the fats, nor yet on the 

 albumens in general, but solely on the fibrine of the blood, 

 which it changes into peptone. Almost the only purpose 

 which it serves is thus to dilute the contents of the intestine. 1 

 The secretion of this fluid takes place by means of chemical, 

 especially acids, or mechanical excitants, such as the pres- 

 ence of a foreign body. In some pathological cases it is 

 secreted in great abundance, producing the serous diarrhoea 

 which is sometimes so alarming. 



Daily observation has long shown what is the influence of 

 the nervous system in producing the flow of the intestinal 

 fluids. The eifect produced on the action of the intestinal 

 tube by certain moral impressions, and the untoward increase 

 of the fluid products, which sometimes accompanies a strong 

 sensation or fear or of danger, is a familiar occurrence. 

 Direct experiments on animals have shown that this is caused 

 by reflex paralysis of the nerves of the intestine, particularly 

 the vaso-motor nerves. If two ligatures be placed around the 

 intestine at some distance from each other, and the nerves 

 leading to the part included between them be cut, the veins 

 and arteries being carefully avoided ; and if then the intestine 

 be replaced, this intestinal loop will be found on the follow- 

 ing day distended by a considerable quantity of clear, alkaline, 

 and very thin fluid, strongly resembling the enteric juice. 

 An additional proof of the influence of the nerves consists in 

 enclosing another intestinal loop between two ligatures, avoid- 

 ing, however, the nerve threads. The mucous of this part of the 

 intestine, instead of being saturated with fluid, is found sticky 

 to the touch, and nearly dry, as in an intestine during fasting. 2 



The pancreatic juice is also called the abdominal saliva ; 

 as the structure of the pancreas resembles that of the salivary 

 glands, so its secreted product closely resembles the saliva ; 

 it differs from it, however, in the proportion of solid matter, 

 for it contains only 90 per cent of water, while the saliva 

 contains 99 per cent. The pancreatic juice is, therefore, 



1 Fide Boylston Prize Essay, " On Intestinal Digestion," by G. 

 M. Garland. D. Clapp & Son, Boston. 



2 A. Moreau, " llecherches sur la Secretion Intestinale." 

 (Comptes-rendus de la Societe de Biologic, IS'JO.) 



