May 21, 1909] 



SCIENCE 



801 



are the most gradual; and as the structure grows 

 more complex, construction becomes more difficult, 

 and collapse is more imminent. It should be dis- 

 tinctly understood, however, that it is not the 

 mere size of the molecules that makes them labile, 

 but rather the manner in which they are linked 

 together and the amount of potential energy which 

 is included in the molecule. 



It is probable that in the absorption of 

 energy by the living molecule, oxygen is 

 released from combination with carbon 

 or hydrogen, and is attached to nitrogen, 

 while in the liberation of energy the inverse 

 takes place. Nitrogen and phosphorus, 

 sometimes with iron and manganese, seem 

 to be, as it were, the master elements within 

 the living molecule. It is by virtue of 

 their chemism that groups are detached 

 from extracellular matter, taken into the 

 living molecule, and assimilated by an 

 atomic rearrangement; and, furthermore, 

 it is on account of the lability of the com- 

 pound thus formed that potential energy 

 is converted into kinetic and all work is 

 accomplished. 



Life is function and not form, and more- 

 over it is a molecular function. The cell 

 is made up of many and possibly of diverse 

 molecules, but it is the function of the in- 

 tracellular molecules that determines the 

 nature of its activities. The following quo- 

 tation from Nussbaum, as given by Loeb, 

 shows that the biologist recognizes that the 

 cell is not the unit of life. 



The cell is not the ultimate physiologic unit of 

 life, even though it must remain such for the 

 morphologist. We are, however, not able to tell 

 how far the divisibility of a cell goes, and how we 

 can determine the limit theoretically. Yet, for 

 the present, it will be well not to apply to living 

 matter the conceptions of atoms and molecules 

 which are well defined in physical chemistry. The 

 notion. Micella, introduced by Naegele, might also 

 lead to difficulties, as the properties of living mat- 

 ter are based upon both nuclein and protoplasm. 

 The cell consequently represents a multiple of 

 individuals. 



Pfliiger has shown that the egg, which 

 has been thought to be a biologic unit, can 

 give rise to many individuals, and Loeb 

 states that his own experiments, as well as 

 those of Drieseh, confirm this finding. 



In his interesting monograph on the 

 "Biogen Hypothesis," Verworn objects to 

 saying that a molecule lives. He states 

 that this is illogical. 



A living thing is only that which demonstrates 

 the phenomenon of life — something that changes 

 itself. A molecule of a given compound, so long 

 as it remains unchanged, can not be said to be 

 living. 



Then, in order not to speak of living 

 molecules, he introduces the term "biogen 

 molecule." Surely, this is a distinction 

 without a difference. I agree with the 

 distinguished German physiologist that a 

 molecule of a cell, so long as it remains 

 unchanged, can not be said to be living, 

 but the point is that living molecules do 

 not remain unchanged. "When life is latent, 

 as it is in spores, seeds and ova, the mole- 

 cule can not be said to be alive, neither are 

 the cells alive; but when placed under fa- 

 vorable conditions, the change between 

 atomic groups in the molecule and the ex- 

 tracellular food substance begins, and life 

 manifests itself. A seed contains the germ- 

 inative cell, a specific ferment and the 

 stored food. The seed is not alive ; it pos- 

 sesses only latent life. So long as it re- 

 mains merely a seed the ferment has no 

 action on the stored food, but place it under 

 suitable conditions of temperature and 

 moisture and the ferment begins to break 

 down the stored protein, and as a result of 

 the chemical cleavage induced by the fer- 

 ment, relatively simple nitrogenous bodies, 

 such as the mono-amino acids, tyrosin and 

 leucin, and the diamino bodies, arginin and 

 .lysin, are formed. These substances begin 

 to react with the molecules within the germ- 

 inative cell, and latent life is quickened into 

 the active form; the mechanism begins to 



