90S Royal Society. 



6. The general and comparative date of accession of the vomit- 

 ing is scarcely compatible with the antiperistaltic theory. 



The author next adduces experiments in which the intestine of 

 animals was artificially occluded by a ligature. In exceptional cases, 

 the ligature sloughed into the canal, and the obstruction was thus 

 destroyed. In all others, the tube was distended above the stricture 

 to a variable extent. Below the stricture, the intestine was usually 

 empty and contracted for an inch or two. The contents of the tube 

 varied both in quality and quantity ; uniform fluidity being asso- 

 ciated with a lar^e quantity of contents, while their smaller amount 

 was often attended with differences of consistence. The date at 

 which the vomiting acceded varied considerably. In one or two in- 

 stances this symptom did not occur at all. These difi^erences ap- 

 peared mainly dependent on — 



1 . The amount of fluid ingesta, 



2. The distance of the stricture from the stomach. 



The date of death seemed to vary chiefly with the degree of dis- 

 tension. 



He therefore deduces the theory, — That, in an obstructed intes- 

 tine, a movement of the ordinary (and probably peristaltic) character 

 propels the contents onwards to the seat of occlusion ; that a con- 

 tinuance of the process distends, first this part of the tube, and next, 

 those portions above it ; that, if the contents are fluid, the ordinary 

 peristalsis tends to develope an axial and reversed current, which re- 

 turns matter from a lower to a higher point of the intestine ; — often 

 from the obstruction to the stomach, whence they are ejected by 

 vomiting. 



That in some cases, however, the action is probably much less 

 perfect than this ; the consistence of the contents preventing the 

 perfection of these currents throughout the whole course of the tube. 

 But still a mixture results, although a less intimate one. 



The author next glances at the mode in which obstruction ap- 

 pears to aff'ect peristalsis, and the nature of the distending fluid. 

 He compares the obstructed intestine to the healthy stomach, to the 

 obstructed artery and duct ; referring its peculiar appearances to 

 the dilatable yet muscular structure of its coats. 



In conclusion, he indicates the possible result of this theory on 

 practical medicine. 



"On the Determination of the Diflference of Longitude, by means 

 of the Magnetic Telegraph." By Elias Looniis, Esq., in a Letter 

 to Lieut.-Col. Sabine, R.A., For. Sec. R.S. Communicated by 

 Lieut.-Col. Sabine, R.A., For. Sec. R.S. 



Tlie writer first refers to a series of experiments made under the 

 direction of Professor Bache, for the determination of the difference 

 of longitude between New York, Philadelphia and Washington, by 

 means of the magnetic telegraph. By this series of experiments he 

 considers it established that, by means of Morse's telegraph, two 

 clocks distant from each other 200 miles, can be compared together 

 with the same precision as if they were placed side by side ; and 

 that the difference of longitude of two places can be determined 

 with the same precision as the relative error of the clocks. These 



