64 ENZYMES 



enzymes is that pepsin destroys trypsin and diastase, while 

 trypsin destroys pepsin. 



So uncertain, however, is our information concerning the 

 chemical nature of the enzymes, that it has become possible for 

 a hypothesis to be developed urging that enzymes are immate- 

 rial, that the actions we consider as characterizing enzymes are 

 the result of physical forces which may reside in many sub- 

 stances, and perhaps even free from visible matter. Arthus, 

 who has been the chief champion of this very interesting con- 

 ception, compares enzyme action to such forces as magnetism. 

 A magnetic iron bar loses its characteristic property when 

 sufficiently heated, just as an enzyme does. Dissolve the mag- 

 net or the enzyme in strong hydrochloric acid and they both 

 lose their power to affect other substances. It has been equally 

 impossible to isolate enzymes and magnetism, both of which 

 are recognized by their actions, and not by themselves. Just 

 as light, heat, and electricity were once considered as matter, so 

 has it also been with enzymes, and Arthus believes that they 

 will eventually be stricken from the list of material things and 

 considered as forms or a form of energy. There can be no 

 question that this conception rests on strong grounds, and it 

 possesses the stimulating qualities that make a hypothesis help- 

 ful, but, as Oppenheimer says, all chemical substances may be 

 considered in the same way. We recognize all bodies through 

 some form of energy ; if we speak of sulphuric acid, it is really 

 of the properties of energy it shows, such as its taste, which is 

 the energy imparted by its ions to the nervous system ; or its 

 combining with bases, etc., which .also is a manifestation of 

 energy. In the same way we recognize the ferments, and we 

 may properly believe them to be fully as much definite sub- 

 stances as is sulphuric acid. The magnet comparison also 

 falls when we remember that the magnetism can be introduced 

 into a bar of iron and removed at will, but as yet it has not 

 been possible to introduce enzymatic properties into an inert 

 proteid, or to restore them to an enzyme that has been 

 destroyed by heat. 



Another valuable piece of evidence of the material existence 

 of enzymes is their specific nature, lipase affecting only fats, 

 and trypsin only proteids, indicating chemical individuality. 

 They are true secretions, formed within the cell by recognizable 

 steps ; and, furthermore, when injected into the body of an ani- 

 mal, they give rise to the formation of specific immune bodies 

 that antagonize their action. Emil Fischer's work with the 

 sugar-splitting enzymes, moreover, indicates that they owe their 



