PRACTICAL EXERCISES 



459 



50 grammes of powdered cane-sugar mixed with lard, the mixture being 

 rolled into little balls. 



(1) After a quarter of an hour put A under chloroform or the A.C.E. 

 mixture, and fasten it on a holder. Kill the animal with chloroform, 

 open the abdomen, tie the oesophagus, place double ligatures on the 

 pyloric end of the stomach and the lower end of the small intestine, and 

 divide between them. Cut out the stomach and intestine ; wash their 

 contents into separate vessels, and test the reaction with litmus paper. 

 Add water and rub up thoroughly. Filter. Wash the residue re- 

 peatedly with small quantities of water, and pass all the washings 

 through the filter. Make up each of the two filtrates to 200 c.c. 



(a) Test the filtrates from the contents of the stomach and intes- 

 tines qualitatively for dextrose by Trommer's (p. 10) or Fehling's 

 (p. 517) and the phenyl-hydrazine test (p. 517). 



(b) If no reducing sugar is present, add to 20 c.c. of each filtrate I c.c. 

 of hydrochloric acid, boil for half an hour, and again test for reducing 

 sugar. If it is now found, some cane-sugar is present. 



(c) If reducing sugar is found, estimate its amount as dextrose by 

 Fehling's solution (p. 518) in a measured quantity of the original 

 filtrate of the gastric or intestinal contents before and after boiling 

 with one-twentieth of its volume of hydrochloric acid. 



(d) Estimate in the same way the amount (as dextrose) of the invert 

 sugar in the standard solution of cane-sugar after inversion, and before 

 inversion if it gives the qualitative test for reducing sugar before it has 

 been boiled with acid. 



From the data obtained (and taking 95 parts of cane-sugar as equal 

 to 100 parts of dextrose) calculate the amount of cane-sugar absorbed, 

 left unchanged, and inverted, though not absorbed. 



(2) One and a half hours after the meal anaesthetize B, and proceed 

 as in (i). 



(3) Two hours after the meal proceed in the same way with C. But 

 in addition observe the lacteals in the mesentery, by gently lifting up 

 a loop of intestine immediately after opening the abdomen. If the 

 absorption of the fat has begun, they will be easily visible, as a network 

 of fine milk-white vessels. Also examine the gastric and intestinal 

 contents with the microscope for fat globules. Compare your results 

 on the amount of sugar obtained from the three animals. Probably 

 much more unabsorbed sugar will be found in C than in B, as the lard 

 hinders it from being dissolved. 



16. Auto-Digestion of the Stomach. In some of the previous experi- 

 ments the stomach of an animal killed during digestion should be 

 removed from the body after double ligation of oesophagus and duo- 

 denum, and placed in a water-bath at 40 C. After several hours the 

 contents should be washed out and the mucous membrane examined. 

 It may be entirely eaten away in parts. 



