250 NEKVOTJS SYSTEM. 



nal brandies of the right nerve is fully illustrated. 1 These 

 experiments show, in the most conclusive and satisfactory 

 manner, that the pneumogastrics influence intestinal as well 

 as gastric secretion. One of the most interesting and curi- 

 ous points in connection with their function is, that after 

 section of the nerves in the cervical region, the most power- 

 ful cathartics, croton-oil, calomel, podophyllin, jalap, arsenic, 

 etc., fail to produce purgation, even in doses sufficient to 

 cause death. The articles used were either given by the 

 mouth, just before dividing the nerves, or were injected un- 

 der the skin. 



Though the observations of Dr. "Wood are not entirely 

 new, they are by far the most extended and satisfactory, and 

 were made with a knowledge of the fact of the distribution of 

 the nerves to the small intestine. Dr. Wood quotes freely from 

 the experiments made by Sir Benjamin Brodie 2 and by Dr. 

 John Reid. 3 Brodie failed to produce purging in dogs when 

 both pneumogastrics had been divided in the neck after the 

 administration of arsenic by the mouth and injecting it un- 

 der the skin. Dr. Reid made five experiments, and in all 

 but one, it is stated that diarrhoea existed after division of 

 the nerves. In twenty experiments by Dr. "Wood, there 

 was no purgation after division of the nerves, in one there 

 was free purgation, and in one there was " some slight muco- 

 fecal discharge." From these, Dr. Wood concludes, that 

 while section of the cervical pneumogastrics, in the great 

 majority- of instances, arrests gastro-intestinal secretion and 

 prevents the action of purgatives upon the intestinal canal, 



1 WOOD, On the Influence of Section of the Cervical Pneumogastrics upon the 

 Action of JZmetics and Cathartics. American Journal of the Medical Sciences, 

 Philadelphia, 1870, New Series, vol. lx., p. 75, et seg. 



2 BRODIE, Experiments and Observations on the Influence of the Nerves of the 

 Eiglitli Pair on the Secretions of the Stomach. Philosophical Transactions, Lon- 

 don, 1814, vol. xiv., p. 104. 



3 REID, Experimental Investigation into the Functions of the Eighth Pair of 

 Nerves. Physiological, Anatomical, and Pathological Researches, London, 1848, 

 p. 245, et seq. 



