and Laboratory Methods. 2023 



Caanon, W.B. The Movements of the Intes- I" 1^98 Cannon published an account 



tine studied by Means of the RontgenRays. of the normal movements of the Stom- 

 Amer. Tour. Physiol. 6:251-277, IQ02. ^ e ^^ ^• • • 1 ^ t j l 



•' J '" y ^^^ q£ |.]^g livmg animal, studied by 



means of the Rontgen rays. The present paper is a continuation of that work 

 and is devoted to an account of the normal movements of the intestines and 

 their contents. The observations were made almost exclusively on cats, and the 

 method of procedure was as follows : Subnitrate of bismuth, one-tenth to one- 

 third the weight of the food, was mixed with what the animal ate. Canned sal- 

 mon was used as food and the animals were not allowed to eat anything during 

 the day preceding an experiment. After any desired interval following the feed- 

 ing the animal was placed in a holder and exposed to the action of the rays. The 

 outline and movements of any part of the alimentary tract containing the bismuth 

 subnitrate could then be seen very clearly on the fluorescent screen. Records 

 were taken, both by means of radiographs and by means of tracings made with 

 a soft pencil on tissue paper laid over the fluorescent surface of the 

 screen. 



The author's more important conclusions regarding the movements of the in- 

 testine are as follows : The activity most commonly seen in the small intestine 

 is the simultaneous division of the food in a coil into small segments, and a 

 rhythmic repetition of the segmentation each time applied to the new segments 

 formed from parts of those just divided. This segmentation may proceed at the 

 rate of thirty divisions per minute. The segmenting activity serves primarily to 

 thoroughly mix the food with the digestive juices, and to bring the digested food 

 into close contact with the absorbing mechanisms. Peristalsis is usually com- 

 bined with segmentation. The ileocoecal valve is found to prevent perfectly the 

 passage of the normal contents of the colon back into the small intestine, al- 

 though allowing such passage in the case of material, whether fluid or mushy, 

 introduced in large amount by the rectum. The usual movement of the trans- 

 verse and ascending colon and the coecum is an antiperistalsis. This recurs in 

 periods about every fifteen minutes, and each period lasts about five minutes. 

 The entrance of new food into the large intestine produces a strong general con- 

 traction along the ccEcum and ascending colon, forcing some of the food onward ; 

 this contraction is immediately succeeded by the antiperistaltic waves. Deep tonic 

 constrictions carry the material from the transverse into the descending colon. 

 No evidence of antiperistalsis in the small intestine has been found. Signs of 

 emotion, such as fear, distress or rage, were found to be accompanied by a total 

 cessation of intestinal movements. The movements continue in the cat both 

 during sleep and at night. 



The paper certainly forms a noteworthy " contribution to a clear understand- 

 ing of the normal movements of the intestine and their contents." r. p. 



Levene.P.A. Recent Researches on the Chem- A brief review and critical discussion 

 istry of the Proteid Molecule. Arch, of ^f t^e recent literature on the chemis- 

 Neurol. and Psychopathol. 3: 1-14, 1901. 



try of proteids. The author reaches 



the conclusion that but little progress has been made in this subject in recent 



years. R. p. 



