II 



EXTERNAL DIGESTIVE SECRETIONS 



137 



Barbara's results are plain from the accompanying diagram 

 (Fig. 51). As it shows, during an absolute fast the quantity of 

 bile secreted in each hour oscillates slightly round a minimum 

 (4-5 grins, in a dog of about 20 kilos.). This amount of bile, 

 secreted during hunger, is not perceptibly affected by the ingestion 

 of water, even in considerable quantities, provided the animals had 



FIG. 51. Diagram to show course of bile secretion in fasting and with different kinds of diet, in a 

 healthy dog of 20 kilos., operated on four months previously by complete and permanent 

 fistula of gall-bladder. (Burbera.) Continuous line shows course of bile secretions during 

 abstinence or injections of water only ; the line of crosses, after injection of 500 grins, horse- 

 flesh ; the dotted line, after ingestion of 100 grms. cane-sugar ; the broken and dotted lint-, 

 after ingestion of 100 grins, fresh butter ; the broken line, after mixed diet of 300 grm.s. flesh, 

 30 grms. butter, and 300 grins, bread. 



not previously been deprived of water for any length of time, in 

 which case the bile is denser than usual. 



A meal of protein is followed by a very marked increase in bile 

 elimination, which commences after about 30 minutes, reaches its 

 maximum after four hours, and then declines till it ceases entirely 

 in about fourteen hours. 



A meal of fats is followed by marked increase in bile 

 secretion, which commences after about one hour, reaches its 

 maximum after about five hours, and drags on with a slow decline 

 till it stops after about twenty hours. 



A meal of carbohydrates is followed by a slight increase in 



