136 Researches Regarding Cholera. [parti. 



normal in appearance, but here and there coated with a thin layer of sanguineous 

 exudation. 



In all cases careful dissections were made, in order to ascertain without doubt 

 that no mistake existed in regard to the actual division of the nerves. In not 

 a single instance was there the slightest evidence of any increase in the secretion 

 of intestinal fluid ; on the contrary, the mucous membrane in the majority of cases 

 was pale and somewhat dry in aspect. In no instance was there any affection of the 

 membrane beyond mere small patches of congestion, or of a thin layer of sanguineous 

 exudation, but not more marked than may frequently be observed in jpost-mortenh 

 examinations of healthy amimals which have died under the influence of chloroform 

 without having been subjected to any operation, and which, if they were in any 

 degree due to the operations in question, were fairly ascribable to the irritation and 

 tendency to inflammation induced by the opening of the abdominal cavity and the 

 handling of its contents. 



Increased activity in the intestinal contractions was in no case observed ; but as 

 this was not the subject of immediate inquiry, and as the openings in the abdominal 

 parietes were closed as rapidly as possible on the completion of the operation, it may 

 well have occurred and yet have escaped notice, 



B.— Section of the Mesenteric Nerves. 



These experiments having failed to achieve the end in view, it was still necessary 

 to repeat Moreau's experiment exactly, as the possibility remained of the semilunar 

 ganglia and solar plexus acting as an independent nervous centre in regulating the 

 secretion of the mucous membrane. 



The operation in this case, although in some respects apparently much simpler 

 and more easy of performance than that of section of the splanchnic nerves, is yet 

 beset with difiiculties peculiar to itself, and which render great care in its performance 

 necessary. The nerves, as is well known, lie close to the vessels, and are of such 

 small size as to render careful dissection necessary in order to secure their thorough 

 division, and it is in this dissection that the difiiculty of the operation lies; for, 

 if the vein be much disturbed, or in any way roughly handled, coagulation of its 

 contents occurs at the isolated portion, and is followed by extreme congestion of 

 the mucous membrane and mesentery, with extravasation between the layers of the 

 latter, and effusion of blood into the cavity of the gut to such an extent as to 

 deprive the observation of all value in regard to the point immediately at issue. 

 Cases of this kind will be given in detail farther on, and the matter is mentioned 

 here only with the view of pointing out that the operation is by no means so 

 simple and easy of performance as might be supposed. The circulation in the 

 portion of gut under operation not unfrequently ceases for a time owing to another 

 cause — the arterial coats when irritated often contract to such a degree as to 



