766 



SCIENCE. 



[N. S. Vol. XXIV. No. 624. 



active gastric peristalsis under a closer ap- 

 proximation to physiological conditions than 

 the saline bath affords. Mere inspection of 

 the abdomen of a rabbit in this position shows 

 that the stomach is far from inert. A short 

 time after preparing the animal, peristaltic 

 waves are seen coursing over the stomach from 

 left to right, increasing in strength as the 

 pyloric third is approached. These waves are 

 easily registered by placing a tambour over 

 the stomach region to be studied and connect- 

 ing it with a writing tambour or manometer. 

 The writing tambour registers not only the 

 change in volvmie of the stomach part it over- 

 lies, but also the respiration of the animal; 

 in many cases, with delicate adjustment of 

 the writing pen, the heart beats are also 

 marked. 



A study of gastric peristalsis by this method 

 has shown that as a rule the stomach is 

 motionless for awhile after the animal is 

 placed upon its back and its limbs are ex- 

 tended, but that active peristalsis is reestab- 

 lished a few minutes afterward. Cessation of 

 gastric peristalsis is also caused by the opera- 

 tion of opening the abdominal cavity, by sec- 

 tion of both vagi in the neck and by subcu- 

 taneous injection of morphin. Inhibitory ef- 

 fects are also caused by ordinary inhalation of 

 ether and by fasting. Intravenous injection 

 of curare does not abolish gastric peristalsis 

 so long as artificial respiration is maintained. 

 Feeding reestablishes peristalsis after its dis- 

 continuance from fasting. 

 Reflex Inhibition of the Cardia in Babbits by 



Stimulation of the Central End of the 



Vagus: S. J. Meltzeb and John Auer. 



At the last meeting the authors reported 

 that by stimulation of the central end of the 

 vagus a tetanic contraction of the entire 

 esophagus can be produced in dogs and cats, 

 but not in rabbits. In continuation of their 

 studies the authors have found that stimula- 

 tion of the central end of the vagus causes a 

 distinct inhibition of the cardia in rabbits. 

 The cardia of the rabbit is normally con- 

 tracted in a moderate degree. Furthermore, 

 at each deglutition the peristaltic movements 

 of the esophagus terminate in a characteristic 

 contraction of the cardia — it sinks into the 



stomach. Finally, after a stimulation of the 

 peripheral end of the vagus the cardia con- 

 tracts in the same characteristic way. The 

 authors found that these three states of con- 

 traction can be definitely inhibited by a stim- 

 ulation of the central end of the vagus. In 

 the first place the cardia relaxes — ^bulges up 

 during such stimulation. In the second place, 

 if deglutition occurs, the cardia fails to con- 

 tract so long as the central end of the vagus 

 is being stimulated. Finally, the interrup- 

 tion of the stimulation of the peripheral end 

 of the vagus does not bring on a contraction 

 of the cardia while the central end is being 

 stimulated. 



Continuous Anesthesia by Subcutaneous In- 

 jection of Magnesium Sulfate in Neph- 

 rectomized Animals: D. E. Lucas and S. J. 

 Meltzer. 



Nephrectomy prevents rapid excretion of 

 magnesium sulfate after its subcutaneous in- 

 troduction. Consequently half the dose of 

 this salt that is required per kilo to anes- 

 thetize a normal rabbit suffices for a neph- 

 rectomized rabbit. Furthermore, the anes- 

 thesia caused in nephrectomized rabbits by 

 half the usual dose is deeper and lasts longer, 

 because most of the magnesium compound is 

 unable to leave the body. The anesthetic 

 results with magnesium sulfate, in normal and 

 nephrectomized rabbits, are in sharp contrast 

 to the toxic effects of strychnin under an- 

 alogous circumstances. 



BemarJcs on and Exhibition of Specimens of a 

 Meta^tasising Sarcoma of the Bat: Simon 

 Flexner and J. W. Jobling. 

 The exhibited specimens consisted of a 

 mixed-cell sarcoma, of the seminal vesicle of 

 a white rat, which had been transplanted suc- 

 cessfully into a series of white rats. The 

 original tumor, which was found in a rat 

 dying spontaneously in the laboratory, was as 

 large as a walnut. Its surface was covered 

 with peritoneum and its consistence was firm. 

 Thus far it has been transplanted to full- 

 grown and young rats both by subcutaneous 

 and by intraperitoneal inoculation. The fea- 

 tures of the tumor which the authors especial- 

 ly emphasized were the large and numerous 



