364 



Some Observations relating to the Function of Digestion. By A. P. W. 

 Philip, M.D. F.R.S.L.SfE. Read January 16, 1829. [Phil. 

 Trans. 1829, p. 137.] 



The author, referring to his former papers published in the Philo- 

 sophical Transactions, concludes that digestion requires for its due 

 performance, both a proper supply of gastric secretion, and a certain 

 muscular action in the stomach ; the latter circumstance being re- 

 quired for the expulsion of that portion of food which has been acted 

 upon by the gastric juice. Nervous power is necessary for secretion ; 

 but the muscular action of the stomach being excited by the mecha- 

 nical stimulus of the contents of that organ, is independent of the 

 nervous power. It has already been shown by the author, that after 

 the removal of a portion of the eighth pair of nerves, the galvanic 

 influence directed through these nerves will restore the secretion 

 of gastric juice ; but Messrs. Breschet and Milne Edwards have 

 lately endeavoured to prove, that the same effect results also from 

 mechanical irritation of the lower portions of the divided nerves. 

 The author points out several circumstances which appear to have 

 been overlooked by these gentlemen, and which, he thinks, invali- 

 date the conclusions they have deduced from their experiments. He 

 states that a certain quantity of digested food will always be found 

 in the stomach of the animal for five or six hours after the operation, 

 and even after the lapse of ten or twelve hours, from its being less 

 completely changed, and therefore expelled more slowly than in the 

 natural state. The paper concludes with the recital of experiments 

 made for the author by Mr. Cutler, in which the contents of the 

 stomach of a rabbit, whose eighth pair of nerves, after excision, had 

 been kept mechanically irritated, were compared with those of another 

 rabbit, in which the nerves had not been irritated, and of a third, 

 which had been left undisturbed. All those who witnessed the re- 

 sult of this experiment, among whom was Mr. Brodie, were con- 

 vinced that the irritation of the nerves had no effect whatever in pro- 

 moting the digestion of the food ; neither did it at all contribute to 

 relieve the difficulty of breathing, consequent upon the section of the 

 nerves. 



Experiments on the Friction and Abrasion of the Surfaces of Solids. 

 By George Rennie, Esq. F.R.S. Read June 12, 1828. [Phil. 

 Trans. 1829, p. 143.] 



The first part of this paper is occupied by a rapid review of the 

 labours of mechanicians on the subject of friction, from the period of 

 those of Amontons at the end of the 1 7th century, to those of Cou- 

 lomb and of Vince in the years 1779 and 1784; from which the 

 author draws the conclusion that the progress of knowledge in this 

 department of science has been slow and unsatisfactory, and that a 

 wide field is still left open to experimental investigation. With a 

 view to elucidate several points not yet sufficiently ascertained by 



