20 INTR OD UCTION. 



capable of manifesting their special activity after the death of their 

 parent-cells, apparently possess the power of oxidation, and it is 

 hence possible that these processes in the living tissues may also be 

 referable to such enzymatic activity. Whether this is actually the 

 case is not definitely known. But if so, we are apparently approach- 

 ing a time when what we have heretofore been forced to ascribe 

 to the activity of a special vital force may be explained upon the 

 basis of physical laws which are seen also at work in the non-organ- 

 ized world. For we know that properties which are supposedly 

 characteristic of the enzymes are possessed also by certain elements 

 which are found only in the inorganic world. The most notable 

 properties of the enzymes are their ability to effect an amount of 

 chemical change which appears to be out of all proportion to the 

 quantity of the enzyme present, and the fact that the enzyme itself 

 apparently does not enter into the reaction. These same properties, 

 however, are common to certain metals and their oxides. Bredig 

 and von Berneck showed that a gram-atomic weight (193 grams) of 

 colloidal platinum diffused through 70,000,000 liters of water shows 

 a perceptible action on more than 1,000,000 times the quantity of 

 hydrogen peroxide ; and H. C. Jones demonstrated that the reac- 

 tion which here takes place is a mono-molecular reaction, which 

 indicates that the platinum itself does not enter into the reac- 

 tion. Ernst has similarly shown that 0.0001 gram of colloidal 

 platinum can catalyse 50,000 times its own weight of oxyhydrogen 

 at ordinary temperature, without loss of efficiency on the part of 

 itself. Curiously enough, the analogy between the action of such 

 metallic solutions and that of the enzymes goes still further. Finely 

 divided platinum, palladium, iridium, osmium, etc., thus have the 

 power of inverting cane-sugar, like one of the enzymes, invertin ; 

 and certain poisons, such as hydrocyanic acid, sulphuretted hy- 

 drogen, carbon disulphide, and mercuric chloride, which inhibit or 

 even suspend the action of the enzymes entirely, exert a similar 

 influence upon a solution of colloidal platinum (negative catalysers, 

 anticatalysers,or paralysers) ; 0.000,000,001 gram of hydrocyanic acid 

 per c.c. will thus reduce the catalytic action of 0.000,006 gram of 

 colloidal platinum upon hydrogen peroxide to one-half. Without 

 entering upon this very interesting subject further, it is clear that a 

 path has been opened upon which it may be possible to penetrate 

 into the mysteries of the so-called vital forces, and to show ulti- 

 mately that such forces are essentially the same as those met with 

 in the non-living world. 



Chlorophyl. In the light of more recent investigation, it seems 

 probable that some of the synthetic processes which occur in plant- 

 life may also be referable to the action of enzymes. As a matter 

 of fact, such bodies are abundantly present in the vegetable world, 

 and we know that some of these at least, and probably all, are 

 characterized by a reversible activity. Maltase, a ferment, which, 

 as we shall see later, causes inversion of the disaccharide maltose to 



