December 20, 1912] 



SCIENCE 



851 



stances. In the formation of a crystal we 

 conceive of certain energies working in 

 certain ways. Every formative event in an 

 organism is a phenomenon of matter in mo- 

 tion. The investigation of form and or- 

 ganization reduces ultimately to an in- 

 vestigation of the energies involved in the 

 motions and configurations of certain sub- 

 stances — biophysics. "We would know the 

 nature and mode of operation of these 

 energies. Are they resultants or complexes 

 of forms of energy with which we feel our- 

 selves somewhat more familiar as we view 

 them in the non-living? Or shall we find 

 that living substance serves as the vehicle 

 for energies peculiar to itself? In the lat- 

 ter case we shall simply have lengthened 

 the known list of truly physical agents 

 that is, agents which are involved in the 

 motions of molecules capable of analysis 

 into known chemical elements. If any pe- 

 culiar energetic properties of living sub- 

 stance should be demonstrated, whether 

 such energies should be regarded as phys- 

 ical or non-physical is a question, not of 

 fact, but merely of terminology. 



But before we can preface our inquiry 

 with "what" and "how," we must first 

 ask, where? Our problem of organization 

 is to a large extent the problem of deter- 

 mining the situation of the energies in- 

 volved in the formation and harmonious 

 operation of organic systems. One impor- 

 tant step has already been gained. It is 

 not so long since we looked hopefully to the 

 environment in which the animal lives as 

 the seat of some, if not all, of the energies 

 of organization. Now we know that the 

 germ possesses something more than merely 

 the fundamental capacities for metabolism 

 and growth. It is not a bit of indifferent 

 plastic substance which is molded into 

 shape by an elaborate complex of environ- 

 mental forces. The energies which under- 

 lie organization are seated in the living 



substance itself. "We now press our ques- 

 tion one step further. "Where, in relation 

 to each system of the organism, are the 

 energies which produce the organization of 

 that system? Does each organic unit con- 

 tain within itself an energy-complex suffi- 

 cient for the part played by that unit in 

 the system to which it belongs and in all 

 higher systems, or shall we find more com- 

 prehensive energy-complexes transcending 

 and dominating the intrinsic energies of 

 all the units of a system? 



It is in the developing organism that 

 this problem of organization most insist- 

 ently demands our attention. There we 

 see the complex arising from what appears 

 to be simple, system growing out of system, 

 one organization after another derived 

 from something which gave within itself no 

 evidence of the existence of such organiza- 

 tions. The adult organism presents more 

 nearly a static condition. "When we under- 

 stand how organic systems arise in onto- 

 geny, we shall doubtless be in a fair way to 

 know, if we do not then already know, how 

 organization is maintained in the adult. 

 Not only is the problem essentially a prob- 

 lem of the developing organism, but de- 

 velopment offers to the investigator the 

 most promising field of attack. He is by 

 no means restricted to embryonic develop- 

 ment. Eegenerative development involves 

 essentially the same processes as embryonic 

 development. Precisely the same prob- 

 lems exist in both and for obvious practical 

 reasons there are great advantages in favor 

 of experimentally controlled regeneration 

 as a means of discovering the location of the 

 energies which produce organization. 



Units of organization representing at 

 least the more conspicuous grades of units 

 which we see in the adult appear early in 

 the ontogeny of metazoa. At first we see 

 cells only, but very soon they become dis- 

 posed in sheets or layers which, so far as 



