INFLUENCE OF ROENTGEN RAYS UPON .METABOLISM 879 



tributable to the effect of x-rays. He concludes from his experiments on 

 the digestion of egg albumin by pepsin and of starch by diastase that a 

 short radiation by x-rays has the effect of accelerating enzyme activity 

 while a longer radiation inhibits it, and that between these two intervals 

 there is a non-effective point. The experiments of Richards show that the 

 effects are slight but definite. 



Radium rays, Avhich are in general comparable with x-rays in their 

 action, have been thought to be the cause of quite marked changes in the 

 course of enzymatic action. Neuberg(&) found an acceleration of theauto- 

 lytic processes under the action of radium emanation. Packard considers 

 that radium radiations, by activating autolytic enzymes, act indirectly 

 upon the chromatin and protoplasm and thus bring about the degenera- 

 tion of the complex proteins and probably affect other protoplasmic sub- 

 stances in the same manner. Influence of radium emanation upon 

 autolysis of normal and pathological tissues has been studied by Lowen- 

 thal and Edelstein. They found that the rate of increase in autolysis 

 varied with the character of the material allowed to autolyze, but 

 the greatest accelerating influence was found in the case of human car- 

 cinoma. 



Henri and Mayer in studying the action of radium on ferments found 

 that invertin, emulsin and trypsin exposed to radiations decreased and 

 finally lost their activity. Bergdell and Bichel observed that the activity 

 of pepsin is enhanced by the influence of radium rays. Schmidt-Nielson 

 showed that radium preparation of 1,800,000 activity has slight inhibiting 

 action upon rennin. Wilcock has reported that radium rays are in- 

 jurious to digestive ferments such as pepsin, trypsin, and ptyalin. Ac- 

 cording to Lowenthal and Wolgemuth radium emanation is capable of ac- 

 celerating the activity of the diastatic enzyme of the blood, liver, saliva, or 

 pancreas, that there may be a slight retardation which is replaced by 

 acceleration if the experiment is sufficiently prolonged. Brown found 

 that the very radioactive radium D, radium E, and radium F have a 

 marked inhibitory action upon pepsin and pancreatic diastase; but no 

 effect upon the autolytic enzyme of the dog's liver. Marshall and Rown- 

 tree's(a) investigation showed that the radium emanation has no accelerat- 

 ing influence upon the lipase of the pig's liver or castor oil bean, while in- 

 hibition of the enzymatic activity is suggested. Schulz(fr) observed that 

 radium emanation has a certain amount of accelerating action upon the 

 uric-acid forming enzymes of the spleen. 



From the fact that alterations in permeability may cause cell division 

 and such metabolic changes as increased elimination of carbon dioxid, of 

 catalase, and an increase of oxygen absorption and various other physio- 

 logical reactions in the cell Richards (c) performed experiments on x-radia- 

 tion as a cause of permeability changes but was unable to find any evidence 

 that alterations in cell metabolism are due to permeability changes. Min- 



