ABSORPTION 219 



follows. Inhibit this movement by applying a solution of calcium 

 chlorid or magnesium chlorid. 



7. Secretion of Intestinal Juice into Excised Loops. Empty a loop 

 of small intestine about 10 cm. in length by gentle pressure exerted with 

 your fingers. Place two pairs of ligatures around the intestine so as to 

 isolate this segment. Ligate the corresponding blood-vessels. Re- 

 move this segment from the body by cutting between each pair of 

 ligatures. Kill the animal by an overdose of ether. Suspend the ex- 

 cised loop at 38 C. in a measured quantity of M/8 sodium chlorid to 

 which from one-seventieth to one-fiftieth of its volume of M/8 barium 

 chlorid has been added. Keep the ends of the intestinal segment above 

 the surface of the solution. Observe the peristalsis. After about 

 twenty minutes measure the quantity of fluid which has been secreted 

 into the lumen of the segment. Since the quantity of the fluid surround- 

 ing this loop has not been lessened, the secretion must have been 

 formed from the material stored in the cells at the time of their removal 

 from the body. 



8. Influence of Adrenal Extract on Intestine. Remove a piece of 

 duodenum, about 10 cm. in length, and place it in cold Ringer's solu- 

 tion. After a time cut off a piece 2 cm. in length and suspend it in a 

 beaker filled with Ringer's solution. Connect its lower end with a 

 weight placed upon the bottom of the receptacle and its upper end 

 with a writing lever properly counterpoised. 



Place a small flame underneath the beaker and slowly raise the 

 temperature of the fluid to 30 C. Start the recording drum and reg- 

 ister the movements of this strip. 



Add 0.5 c.c. of adrenalin to the Ringer fluid (300 c.c.). Note the 

 effect upon the length of the strip (tonus) as well as upon its con- 

 tractions. 



9. Rapidity of Absorption and Elimination. Into each of ten test- 

 tubes pour 5 c.c. of thin starch paste and 2 c.c. of concentrated nitric 

 acid. Swallow a capsule containing 10 grains of potassium iodid and 

 rinse your mouth thoroughly. Increase the secretion of saliva by chew- 

 ing a piece of paraffin and collect at intervals of two minutes a quantity 

 of saliva in the corresponding test-tubes. Rinse the mouth after each 

 collection. How soon after ingestion can this agent be recognized in 

 the saliva? 



10. Histologic Examination of Preparations of Intestinal Mucosa. 

 Study the structure of a villus, mucous cells, and glands of Lieberkiihn. 



