ARTICLES 411 



and that adsorption was in some way related to the amount of 

 ionisation. In the same paper, however, he notes that charcoal 

 could remove as much enzyme as albumin and even more than 

 casein — facts which do not support his hypothesis. The 

 exact significance of the experiments will be seen later to 

 depend on the condition of the substrate as investigated by 

 Ringer. 



Specificity. — ^The question of adsorption in relation to 

 enzymes is further complicated by their specificity. Specific 

 catalysts and specific adsorption are known to exist in the 

 inorganic world, but specificity is more marked in the case of 

 enzymes, although many would reason that the specificity is 

 by no means absolute, and in the light of further knowledge 

 may be found to be non-existent. Many investigators are 

 just as determined in the opposite direction. It is perhaps 

 but natural that the question should have excited much con- 

 troversy, as it is so closely related to that of the adaptation of 

 plants and animals. 



Following up the early work of Duclaux, who showed 

 that the enzymes of yeast differed according to the medium 

 on which the yeast was grown, Abderhalden and Kapfberger 

 (1910) found that on injection of protein and carbodydrates 

 enzymes were developed which hydrolysed these substances. 

 This work however has not been wholly verified. In 19 16 

 Hulton found that parenteral injection of protein does not 

 increase the proteoclastic enzymes in rabbit serum ; but 

 Watanabe (191 7) claimed that the blood diastase in rabbits 

 was increased by the injection of human saliva and the paren- 

 teral administration of starch. Hatta and Marui (191 8) showed 

 that the diastatic power of the pancreatic juice was much 

 reduced if the animal was fed on a fat diet. The earlier work 

 of Benjamine, which was published in 191 5 but apparently 

 delayed in its translation till more recently, had shown that 

 the method of administration made considerable difference in 

 the results. This investigator found that when sucrose was 

 given parenterally sucrase appeared in the blood, but this 

 did not occur if the sucrose was given enterally. He also found 

 that lactose feeding or injection caused lactase to appear in the 

 juices of the pancreas and intestine, but not of the parotid. 

 It is pointed out that no lactase was developed when lactose 

 was added to blood, but occurred in organs after perfusion with 

 lactose. The investigations of Lombroso (191 5) brought out 

 further evidence in favour of specificity. He found that the 

 pancreatic juice could invert sucrose after the injection of 

 sucrose intravenously or subcutaneously. In this connection 

 it is interesting to note that Fleischmann and Meyers (191 8) 

 showed that in infancy animals were incapable of digesting 



