METHODS FOR STUDY OF FAT ABSORPTION 



125 



witch, 605 but none of these is entirely free from all of the objections enumer- 

 ated above. Figure 8 gives a diagrammatic representation of some of the 

 variations in the Thiry-Vella fistulas. 



In 1933, Johnston 606 described a modification of the Thiry loop designed 

 to overcome the objection of leakage and to maintain normal peristalsis 

 over a period as long as seven months. Absorption rates for glucose and 

 sodium chloride after the seven-month interval were within the limits of 

 error of experiments made many months earlier. The rate of secretion 

 was maintained at a constant level and enzyme activity was noted in the 



Balloon- M 



51 



Peritoneum 



Fig. 9. The fistula, as devised by Johnston 606 for quantitative studies of 

 intestinal absorption. 



samples obtained seven months after the fistulas were prepared. Histolog- 

 ical sections made after this period showed that no microscopic changes had 

 developed in any of the structures. These data led to the conclusion that 

 the intestinal loops had remained normal after continued usage, and that 

 with ordinary care they will continue to function satisfactorily over a 

 prolonged interval. 



In the Johnston technic, a Thiry fistula is first made from a section of 

 intestine 20 to 50 cm. in length. After the wound is allowed to heal, which 

 requires about two weeks, the loop is provided with a catheter to which two 

 balloons are attached and which will prevent leakage. One of these is 

 fastened in such a position that it lies within the loop, while the outer one is 

 fixed in a position partly within the fistulous tract and partly exposed on the 

 outside of the abdominal wall. When these are properly inflated, the 

 inner balloon closes the proximal end of the loop, and the outer one, which 

 lies entirely upon the abdominal wall, prevents the catheter from being 



605 H. L. White and J. Rabinowitch, /. Biol. Chem., 74, 449-454 (1927). 



606 C. S. Johnston, Proc. Soc. Exptl. Biol. Med., SO, 193-196 (1932-1933). 



