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EL T. Brown and J. Heron. [May 13, 



slowness, when 25 per cent, of the total quantity of cane-sugar has 

 been inverted. The reason for this limited invertive action is by 

 no means clear, and the subject requires further investigation. 



Claude Bernard, who first demonstrated the existence in the small 

 intestine of a soluble ferment capable of inverting cane-sugar, con- 

 sidered that in this property resided one of the most important 

 functions of the succus entericus. By injecting a solution of cane- 

 sugar into the veins and cellular tissue of animals he demonstrated 

 that this carbohydrate, after traversing the system, is eliminated 

 weight for weight in the urine, without undergoing any modification 

 or assimilation. In order that cane-sugar shall be assimilated by the 

 animal or vegetable economy, it must first be inverted. The seat of the 

 invertive action is in the small intestine itself. 



If this function of the small intestine has the importance attributed 

 to it by Bernard, it is in the highest degree probable that the relatively 

 far more active maltose-hydrating ferment, coexisting with the in- 

 vertive ferment, must possess some considerable physiological value. 



It must be remembered that, under natural conditions, the amount 

 of cane-sugar which an animal is called upon at any given time to 

 assimilate is very small when compared with the amount of products 

 derived directly from starch. 



We cannot consider, under these circumstances, that so well-marked 

 and striking a function of the small intestine as that of converting 

 maltose into dextrose can be useless to the animal economy. The 

 most probable explanation is that maltose is incapable of assimilation 

 in its unaltered state, but has first to be broken down to the smaller 

 moleculed dextrose, just as cane-sugar, prior to assimilation, is con- 

 verted into the chemically less complex dextrose and levulose. This is 

 rendered the more probable from the known similarity of composition 

 of maltose and cane-sugar, both bodies belonging to the class of 

 sugars represented by the formula C 13 H 22 O n . 



Whether maltose is capable, under any circumstances, of being 

 directly assimilated is a question, the solution of which we must leave 

 in the hands of experimental physiologists. Probably a series of care- 

 fully conducted injection experiments, similar to those made by 

 Bernard with cane-sugar, would yield the desired information. It 

 is true that the estimation of maltose in urine would be attended with 

 greater difficulties than the estimation of cane-sugar, but these diffi- 

 culties are by no means insurmountable. 



It will be remembered that the action of artificial pancreatic juice 

 upon gelatinised starch is very rapid, the transformation products in a 

 short time containing 80 per cent, of maltose, which is but very 

 slowly and partially converted into dextrose by a continuance of the 

 reaction. The active agent of the small intestine, on the other hand, 

 while exerting but little action upon gelatinised or soluble starch, 



