( 17 ) 



1 — // — 4 ,1 f — 0. 



It slioiild nlso be iiu'iilioiiod that lli(> iii\ oi-lini; enzyme of yeast 

 appears to he always the same \vlie(lier canesu^ai- or maltose has 

 been present as a carbohydrate food. In an ordinary eereal extract 

 a Httle canesngar occurs along with the maltose. A pure yeast- 

 cnlture, cultivated by myself in a solution of pure maltose (phis 

 the necessary salts and nitrogenous food) gave an enzyme extract 

 which was retarded in its action equally much by glucose and 

 laevulose, and twice as mnch by galactose. In the enzyme foi-mation, 

 therefore a partial conversion of glucose into laevulose seems to take 

 place. LoBKY dk BruYxN aiid Alivkkua van Ekenstkin ^) have shown 

 that these two hexoses may be con\erted into each other in aji 

 alkaline solution. 



The investigations of O'Sultjvan and Thompson'') have rendered 

 it probable that the in\ei-tin-molecule (if we may use this expi-cssion) 

 contains a carbohydrate grou[). These investigators have attempted 

 to purify invertin and found that a constant component of the 

 resulting proteid-complex, their so-called i^-invertan, contained 18 

 parts of carbohydrate to one part of albuminoid. 



A further development of the electron theory will probably eluci- 

 date the nature of those enzyme radiations. As Lodge '^) observed, 

 it is not the occurrence of radiations in matter which need cause 

 astonishment but rather ;ne fact that not a great many more radia- 

 tion phenomena have already been discovered. 



Many other catalytic phenomena such as the action of hydrogen-ions 



and those of Hheukj's anorganic ferments may, after all, be due to 



radiations. Fur hydrogen-ions, carriers of loose electrons and dispersed 



platinum cathodes |)robably also emit radiations owing to the motion 



of the electrons in or around the material particle. During the course 



of a same reaction, Bkeuig often noticed an increase of the constant 



1 1 



k=:~lo(i- — iust as that shown bv the invertin action. A retar- 

 t ■' l-y ^ 



dati(ui of the catalysis by indifferent matters has also been frequently 



noticed, for instance, by Knoevenagel and Tomacszewski ') in the 



action of linely divided palladium or platinum on benzoin. 



If the statements of the Fi-ench investigators on the physiological 



1) Rec. Truv. Cliim. 1895 p. -JOl. 



••J) .loiiiii. CIk'iii. Soc. IS'.K) 1). S3i. 



•■>) "Un Ek'ctmiis" .loniii. VWiv. Knginoeis 1903 Vol. 32 p. 45. 



t) Ber. 19U3. 2S29. 



.2 



Proceedings Koyal Acad. Amsterdam. Vol. VII. 



