658 



SCIENCE 



[N. S. Vol. XL. No. 1036 



of which is manifested in an interaction between 

 water and carbon dioxide through the agency 

 of an enzyme in the form of an oxidase to form 

 formaldehyde. During this process there is 

 formed another enzyme, which tentatively may 

 be designated an aldehydase, that reacts with 

 formaldehyde and by polymerization and con- 

 densation of six molecules gives rise to a 

 simple sugar, such as dextrose. At the same 

 time another enzyme appears in the form of 

 maltase, which, reacting with the dextrose 

 causes the formation of maltose, during which 

 reaction another enzyme, a dextrinase, is pro- 

 duced which reacts with the maltose to yield 

 dextrin. Going on with this reaction, another 

 enzyme which may be designated an amylase 

 appears, which, reacting with the dextrin, forms 

 soluble starch. During this stage there arises 

 another enzyme, a coagulase, which converts 

 the starch from the soluble to the insoluble 

 form or ordinary starch. At this stage the 

 series of reactions have reached their end be- 

 cause a state of physico-chemical equilibrium 

 has become established, the ultimate purpose 

 of the processes being attained; that is a 

 form of pabulum of extremely high nutritive 

 value and of extremely low molecular pres- 

 sure, even in soluble form, so that it may 

 entirely and rapidly disappear without dis- 

 turbance of physico-chemical equilibrium in 

 the starch-bearing cells. The mechanism con- 

 cerned in starch-formation is without doubt 

 paralleled in the synthesis of proteins, fats and 

 other complex organic substances, and it is 

 but a step from the individual serial processes 

 concerned in the formation of each of these 

 substances to associated processes whereby 

 there are formed and combined the various 

 substances that constitute the organic struc- 

 tural components of protoplasm. Moreover, 

 such serial processes are reversible at any stage, 

 and so simple a modification as a change in the 

 per cent, of water may, as in the maltose- 

 dextrose-glucase reaction, cause a synthetic 

 change. 



In vitro in both synthetic and analytic 

 processes like those which constitute serial 

 steps in the building up and breaking down 

 of starch, protein, fat and other complex 



organic substances there does not occur in any 

 reaction, as far as known, either a trans- 

 formation or a production of enzyme such as 

 occurs in vivo, hence, when a single enzyme 

 is present it carries out but one step of the 

 reactions, but when, as in the case of diastases 

 as ordinarily prepared, the enzyme is not a 

 single substance or unit body but a composite 

 of a number of enzymes or modifications of 

 a given basic enzyme, serial steps may occur 

 as in vivo. Thus, if only a single enzyme be 

 present formaldehyde may be converted into 

 a monosaccharose, or a monosaccharose into a 

 disaccharose, or a disaccharose into a poly- 

 saccharose such as dextrin, or dextrin into a 

 higher form of polysaccharose such as soluble 

 starch, according to the enzyme or modified 

 enzyme and initial substance present; or the 

 reverse of any one of these processes may occur 

 if proper conditions are present, but never do 

 any two successive progressive or regressive 

 steps occur unless through the agency of two 

 diiierent or modified forms of enzymes which 

 are present. 



It will thus be apparent that the first step 

 of synthesis is determined by the character of 

 the initial physico-chemical mechanism and 

 that all subsequent reactions under given con- 

 ditions are definitely predetermined; in other 

 words, the entire train of reactions depends 

 inherently upon the nature of the initial 

 physico-chemical mechanism of which the 

 enzyme that starts the serial changes is an 

 integral part. 



Having a specific stereochemic system, such 

 a system in accordance with the laws of 

 physical-chemistry can exist in either a latent 

 or active state, and that when in an active 

 state the reaction or reactions are always in 

 the direction of the establishment of equili- 

 brium of solution, every reaction or series of 

 reactions being as definitely predetermined as 

 is every reaction familiar to the inorgani* 

 chemist. The germplasm in the form in which 

 it is secreted may be regarded as being in the 

 nature of an exceedingly complex stereochemi* 

 system which is from its incipiency, or very 

 soon is in a state of physico-chemical un- 

 equilibrium, and in which, as a consequent. 



