DIGESTIBILITY OF FOOD. 311 



ever, extraordinarily different even for one and the same substance, 

 as, for instance, flesh, without our often being able to discover the 

 cause of the difference; this being a point which daily observations 

 on dogs with gastric fistulee have placed beyond a doubt. It very 

 much seems to depend on the quantity of the food taken at once ; 

 if, for instance, we allow a dog to swallow a large quantity of flesh, 

 fragments may be still found in its stomach after six, eight, and 

 even ten hours, while smaller quantities often disappear after less 

 than two hours. And a further reason why the results of Beau- 

 mont's observations cannot be specially applied to physiology or 

 even to dietetics, depends upon the circumstance that he has 

 either not at all or very inaccurately described the quantity of the 

 food that was taken; and upon this circumstance may partly 

 depend the great differences which are often observed in his 

 observations, when made under apparently similar conditions. 



There are still to be mentioned the experiments instituted by 

 C. G. Schultz,* who at a certain time after feeding dogs and cats 

 with different kinds of food, killed them and examined the con- 

 tents of their stomachs. These attempts, from the method by 

 which they were carried out, would deserve great confidence if their 

 results did not differ in so remarkable a manner from those 

 obtained by Beaumont and others, that we are almost compelled 

 to presume that there must have been some essential errors in 

 them. The same is the case with the observations which Lalle- 

 mand instituted on men with gastric fistulse. Blondlot who first 

 introduced into physiology the operation of artificial gastric 

 fistula was so far from being able to attain to definite results, 

 notwithstanding that his observations were made under far more 

 favourable conditions, that he was led to express the view that the 

 digestibility of different articles of diet depended solely on the state 

 of the stomach at the time of the experiment, and that it is pure 

 waste of time to labour at the determination of the digestibility of 

 individual articles of food. 



These few instances are sufficient to indicate that moderately 

 accurate determinations of the digestibility of varieties of animal 

 food are involved in extraordinary difficulties even in relation to 

 gastric digestion alone. At the present time we possess few expe- 

 riments which can afford a fixed point of departure for the deter- 

 mination of the digestibility of different kinds of food. 



My personal experiments, which have reference partly to dogs, 



* Do alimcntorum concoctioiie experimcuta nova. Berol. 1834. 

 t Traite de la digestion, p. 383-409. 



