PRACTICAL EXERCISES 433 



(a) Examine a little of it under the microscope, and make out fat 

 globules, muscular fibres and starch granules. The latter can be 

 recognised by their being coloured blue by a drop or two of iodine 

 solution. 



(b) Filter the chyme, mixing it, if necessary, with a little water, 

 and test it as in 4 (d) (p. 426) for the products of digestion of proteins. 

 In addition, test for starch, dextrin, and reducing sugar. 



(2) One and a quarter hours after the meal inject apomorphine 

 into dog B, and proceed as in (i). 



(3) Two and a half hours after the meal inject apomorphine into 

 dog C, and proceed as in (i). Compare the results from the three 

 specimens of chyme. 



ii.* Quantity of Cane-sugar inverted and absorbed in a Given 

 Time. Take three dogs, A, B, and C, which have fasted for twenty- 

 four hours. The animals should be about the same size. Feed A 

 and B with 100 c.c. of a standard solution of cane-sugar (about a 20 

 per cent, solution) or as much more as they will take. If the dogs 

 have been kept without water for a day they will more readily take 

 the sugar solution. Or it may be given through a tube passed into 

 the stomach, and in this case a larger quantity of sugar can be given. 

 A gag consisting of a piece of wood with a hole in the middle of it, 

 through which the tube is passed, must first be secured in the dog's 

 mouth. Feed C with 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 repeatedly 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) and the phenyl- 

 hydrazine test (p. 488). 



(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. 489) 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 



* See note on p. 432. 



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