343 REPORT — 1875. 



one part being inaufflcient to supply the material for secretion ; for, in Mor- 

 ceau's experiment, the nerves going to a part of the intestine only are divided, 

 and any relaxation of the vessels of that part which succeeds the operation 

 will increase the supply of blood to the intestinal loop operated upon, as the 

 vessels in the after parts stUl retain their normal tone, and the blood naturally 

 flows in the direction of least resistance. When, however, the splanchnics, 

 which are the chief vasomotor nerves of the intestine, are cut and the solar 

 plexus destroyed, the vessels of the whole intestine become dilated and the 

 flow of blood through every part languid. 



Such an explanation appears all the more probable from the fact observed 

 by Cyon and Aladoff that section of the vasomotor nerves of the liver alone 

 increased the flow of blood through the organ and produced diabetes, while 

 section of these same fibres was not followed by this result if the intestinal 

 vasomotor nerves contained with them in the splanchnics were divided at the 

 same time. The reason assigned is that in the former case the blood flowed 

 easily through the dilated vessels of the liver, and a proportionately small 

 quantity through those of the intestine ; while in the latter, the vessels being 

 all dilated, there was not sufiicient pressure to keep up an active circulation 

 anywhere. In order, then, to avoid this source of fallacy, your Committee 

 repeated their experiments on the section of the splanchnics and excision of 

 the solar plexus, but at the same time ligatured the aorta between the mesen- 

 teric and renal arteries, so that the pressure in the vessels of the intestines 

 might be maintained as nearly as possible normal. These experiments also 

 yielded a negative result, so that the failure of the previous series cannot 

 have been due to diminished supply of blood to the intestine. 



Apart from paralytic secretion, a striking result thrice obtained by your 

 Committee was the occurrence of extravasations of blood into the mucous 

 membrane of a great part of the small intestine, and the exudation of a 

 bloody fluid into its lumen, after simultaneous destruction of the solar plexus 

 and of the lower part of the spinal cord (Nos. 18, 19, 20). Although Samuel 

 and Pincus had noticed this after destruction of the solar plexus alone, your 

 Committee only observed it once, under these conditions, in the case of the 

 dog (No. 23) ; while ecchymoses and extravasations were absent in all other 

 cases, even when they succeeded in obtaining a paralytic secretion of fluid. 

 Nor did your Committee observe haemorrhage in any case after destruction 

 of the spinal cord and division of the splanchnics alone, even when this was 

 accompanied by section of the vagi. 



In three out of the six experiments, on the other hand, in which the solar 

 plexus and spinal cord were simultaneously destroyed, extravasations occurred 

 to a most remarkable extent (Nos. 18, 19, 20). In one at least of the 

 others their absence might be accounted for by the weak condition of the 

 circulation. Another result, worthy of special notice, is the occurrence of 

 vomiting in one animal after division of the vagus and splanchnic nerves on 

 both sides. 



While the problem which has baffled so many previous investigations 

 cannot yet be considered as solved, your Committee hope that their experi- 

 ments may be considered to have proved the absence of influence on the 

 intestinal secretion through the splanchnic nerves, the pneumogastrics, the 

 sympathetic above the diaphragm, or the spinal marrow, and the probable 

 influence of the gangha contained in the solar plexus, though certainly not 

 of the two semilunar ganglia exclusively. Also the independent occurrence 

 of hemorrhage and of paralytic secretion appear to point to a separate nervous 

 influence on the blood-vessels and the secreting structures of the intestine. 



